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If a system has isolated CPUs via the "isolcpus=" command line parameter,
then an attempt to offline the last housekeeping CPU will result in a
WARN_ON() when rebuilding the scheduler domains and a subsequent panic due
to and unhandled empty CPU mas in partition_sched_domains_locked().
cpuset_hotplug_workfn()
rebuild_sched_domains_locked()
ndoms = generate_sched_domains(&doms, &attr);
cpumask_and(doms[0], top_cpuset.effective_cpus, housekeeping_cpumask(HK_FLAG_DOMAIN));
Thus results in an empty CPU mask which triggers the warning and then the
subsequent crash:
WARNING: CPU: 4 PID: 80 at kernel/sched/topology.c:2366 build_sched_domains+0x120c/0x1408
Call trace:
build_sched_domains+0x120c/0x1408
partition_sched_domains_locked+0x234/0x880
rebuild_sched_domains_locked+0x37c/0x798
rebuild_sched_domains+0x30/0x58
cpuset_hotplug_workfn+0x2a8/0x930
Unable to handle kernel paging request at virtual address fffe80027ab37080
partition_sched_domains_locked+0x318/0x880
rebuild_sched_domains_locked+0x37c/0x798
Aside of the resulting crash, it does not make any sense to offline the last
last housekeeping CPU.
Prevent this by masking out the non-housekeeping CPUs when selecting a
target CPU for initiating the CPU unplug operation via the work queue.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/202310171709530660462@zte.com.cn
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Pull in upstream to get the fixes so depending changes can be applied.
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When employed within a sleepable program not under RCU protection, the
use of 'bpf_task_under_cgroup()' may trigger a warning in the kernel log,
particularly when CONFIG_PROVE_RCU is enabled:
[ 1259.662357] WARNING: suspicious RCU usage
[ 1259.662358] 6.5.0+ #33 Not tainted
[ 1259.662360] -----------------------------
[ 1259.662361] include/linux/cgroup.h:423 suspicious rcu_dereference_check() usage!
Other info that might help to debug this:
[ 1259.662366] rcu_scheduler_active = 2, debug_locks = 1
[ 1259.662368] 1 lock held by trace/72954:
[ 1259.662369] #0: ffffffffb5e3eda0 (rcu_read_lock_trace){....}-{0:0}, at: __bpf_prog_enter_sleepable+0x0/0xb0
Stack backtrace:
[ 1259.662385] CPU: 50 PID: 72954 Comm: trace Kdump: loaded Not tainted 6.5.0+ #33
[ 1259.662391] Call Trace:
[ 1259.662393] <TASK>
[ 1259.662395] dump_stack_lvl+0x6e/0x90
[ 1259.662401] dump_stack+0x10/0x20
[ 1259.662404] lockdep_rcu_suspicious+0x163/0x1b0
[ 1259.662412] task_css_set.part.0+0x23/0x30
[ 1259.662417] bpf_task_under_cgroup+0xe7/0xf0
[ 1259.662422] bpf_prog_7fffba481a3bcf88_lsm_run+0x5c/0x93
[ 1259.662431] bpf_trampoline_6442505574+0x60/0x1000
[ 1259.662439] bpf_lsm_bpf+0x5/0x20
[ 1259.662443] ? security_bpf+0x32/0x50
[ 1259.662452] __sys_bpf+0xe6/0xdd0
[ 1259.662463] __x64_sys_bpf+0x1a/0x30
[ 1259.662467] do_syscall_64+0x38/0x90
[ 1259.662472] entry_SYSCALL_64_after_hwframe+0x6e/0xd8
[ 1259.662479] RIP: 0033:0x7f487baf8e29
[...]
[ 1259.662504] </TASK>
This issue can be reproduced by executing a straightforward program, as
demonstrated below:
SEC("lsm.s/bpf")
int BPF_PROG(lsm_run, int cmd, union bpf_attr *attr, unsigned int size)
{
struct cgroup *cgrp = NULL;
struct task_struct *task;
int ret = 0;
if (cmd != BPF_LINK_CREATE)
return 0;
// The cgroup2 should be mounted first
cgrp = bpf_cgroup_from_id(1);
if (!cgrp)
goto out;
task = bpf_get_current_task_btf();
if (bpf_task_under_cgroup(task, cgrp))
ret = -1;
bpf_cgroup_release(cgrp);
out:
return ret;
}
After running the program, if you subsequently execute another BPF program,
you will encounter the warning.
It's worth noting that task_under_cgroup_hierarchy() is also utilized by
bpf_current_task_under_cgroup(). However, bpf_current_task_under_cgroup()
doesn't exhibit this issue because it cannot be used in sleepable BPF
programs.
Fixes: b5ad4cdc46c7 ("bpf: Add bpf_task_under_cgroup() kfunc")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Cc: Feng Zhou <zhoufeng.zf@bytedance.com>
Cc: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20231007135945.4306-1-laoar.shao@gmail.com
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A few drivers were missing a xdp_do_flush() invocation after
XDP_REDIRECT.
Add three helper functions each for one of the per-CPU lists. Return
true if the per-CPU list is non-empty and flush the list.
Add xdp_do_check_flushed() which invokes each helper functions and
creates a warning if one of the functions had a non-empty list.
Hide everything behind CONFIG_DEBUG_NET.
Suggested-by: Jesper Dangaard Brouer <hawk@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20231016125738.Yt79p1uF@linutronix.de
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While adding a preferred console handling for serial_core for serial port
hardware based device addressing, Jiri suggested we constify name for
add_preferred_console(). The name gets copied anyways. This allows serial
core to add a preferred console using serial drv->dev_name without copying
it.
Note that constifying options causes changes all over the place because of
struct console for match().
Suggested-by: Jiri Slaby <jirislaby@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20231012064300.50221-2-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Let's check for valid console index values for preferred console to avoid
bogus console index numbers from kernel command line.
Let's also return an error for negative index numbers for the preferred
console. Unlike for device drivers, a negative index is not valid for the
preferred console.
Let's also constify idx while at it.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20231012064300.50221-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:
====================
pull-request: bpf-next 2023-10-16
We've added 90 non-merge commits during the last 25 day(s) which contain
a total of 120 files changed, 3519 insertions(+), 895 deletions(-).
The main changes are:
1) Add missed stats for kprobes to retrieve the number of missed kprobe
executions and subsequent executions of BPF programs, from Jiri Olsa.
2) Add cgroup BPF sockaddr hooks for unix sockets. The use case is
for systemd to reimplement the LogNamespace feature which allows
running multiple instances of systemd-journald to process the logs
of different services, from Daan De Meyer.
3) Implement BPF CPUv4 support for s390x BPF JIT, from Ilya Leoshkevich.
4) Improve BPF verifier log output for scalar registers to better
disambiguate their internal state wrt defaults vs min/max values
matching, from Andrii Nakryiko.
5) Extend the BPF fib lookup helpers for IPv4/IPv6 to support retrieving
the source IP address with a new BPF_FIB_LOOKUP_SRC flag,
from Martynas Pumputis.
6) Add support for open-coded task_vma iterator to help with symbolization
for BPF-collected user stacks, from Dave Marchevsky.
7) Add libbpf getters for accessing individual BPF ring buffers which
is useful for polling them individually, for example, from Martin Kelly.
8) Extend AF_XDP selftests to validate the SHARED_UMEM feature,
from Tushar Vyavahare.
9) Improve BPF selftests cross-building support for riscv arch,
from Björn Töpel.
10) Add the ability to pin a BPF timer to the same calling CPU,
from David Vernet.
11) Fix libbpf's bpf_tracing.h macros for riscv to use the generic
implementation of PT_REGS_SYSCALL_REGS() to access syscall arguments,
from Alexandre Ghiti.
12) Extend libbpf to support symbol versioning for uprobes, from Hengqi Chen.
13) Fix bpftool's skeleton code generation to guarantee that ELF data
is 8 byte aligned, from Ian Rogers.
14) Inherit system-wide cpu_mitigations_off() setting for Spectre v1/v4
security mitigations in BPF verifier, from Yafang Shao.
15) Annotate struct bpf_stack_map with __counted_by attribute to prepare
BPF side for upcoming __counted_by compiler support, from Kees Cook.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (90 commits)
bpf: Ensure proper register state printing for cond jumps
bpf: Disambiguate SCALAR register state output in verifier logs
selftests/bpf: Make align selftests more robust
selftests/bpf: Improve missed_kprobe_recursion test robustness
selftests/bpf: Improve percpu_alloc test robustness
selftests/bpf: Add tests for open-coded task_vma iter
bpf: Introduce task_vma open-coded iterator kfuncs
selftests/bpf: Rename bpf_iter_task_vma.c to bpf_iter_task_vmas.c
bpf: Don't explicitly emit BTF for struct btf_iter_num
bpf: Change syscall_nr type to int in struct syscall_tp_t
net/bpf: Avoid unused "sin_addr_len" warning when CONFIG_CGROUP_BPF is not set
bpf: Avoid unnecessary audit log for CPU security mitigations
selftests/bpf: Add tests for cgroup unix socket address hooks
selftests/bpf: Make sure mount directory exists
documentation/bpf: Document cgroup unix socket address hooks
bpftool: Add support for cgroup unix socket address hooks
libbpf: Add support for cgroup unix socket address hooks
bpf: Implement cgroup sockaddr hooks for unix sockets
bpf: Add bpf_sock_addr_set_sun_path() to allow writing unix sockaddr from bpf
bpf: Propagate modified uaddrlen from cgroup sockaddr programs
...
====================
Link: https://lore.kernel.org/r/20231016204803.30153-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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The number of active retprobes can be zero but it is not acceptable,
so return EINVAL error if detected.
Link: https://lore.kernel.org/all/169750018550.186853.11198884812017796410.stgit@devnote2/
Reported-by: wuqiang.matt <wuqiang.matt@bytedance.com>
Closes: https://lore.kernel.org/all/20231016222103.cb9f426edc60220eabd8aa6a@kernel.org/
Fixes: 5b0ab78998e3 ("fprobe: Add exit_handler support")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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The CSD lock seems to get stuck in 2 "modes". When it gets stuck
temporarily, it usually gets released in a few seconds, and sometimes
up to one or two minutes.
If the CSD lock stays stuck for more than several minutes, it never
seems to get unstuck, and gradually more and more things in the system
end up also getting stuck.
In the latter case, we should just give up, so the system can dump out
a little more information about what went wrong, and, with panic_on_oops
and a kdump kernel loaded, dump a whole bunch more information about what
might have gone wrong. In addition, there is an smp.panic_on_ipistall
kernel boot parameter that by default retains the old behavior, but when
set enables the panic after the CSD lock has been stuck for more than
the specified number of milliseconds, as in 300,000 for five minutes.
[ paulmck: Apply Imran Khan feedback. ]
[ paulmck: Apply Leonardo Bras feedback. ]
Link: https://lore.kernel.org/lkml/bc7cc8b0-f587-4451-8bcd-0daae627bcc7@paulmck-laptop/
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Imran Khan <imran.f.khan@oracle.com>
Reviewed-by: Leonardo Bras <leobras@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Randy Dunlap <rdunlap@infradead.org>
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The cpupid (or access time) is stored in the head page for THP, so it is
safely to make should_numa_migrate_memory() and numa_hint_fault_latency()
to take a folio. This is in preparation for large folio numa balancing.
Link: https://lkml.kernel.org/r/20230921074417.24004-7-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Verifier emits relevant register state involved in any given instruction
next to it after `;` to the right, if possible. Or, worst case, on the
separate line repeating instruction index.
E.g., a nice and simple case would be:
2: (d5) if r0 s<= 0x0 goto pc+1 ; R0_w=0
But if there is some intervening extra output (e.g., precision
backtracking log) involved, we are supposed to see the state after the
precision backtrack log:
4: (75) if r0 s>= 0x0 goto pc+1
mark_precise: frame0: last_idx 4 first_idx 0 subseq_idx -1
mark_precise: frame0: regs=r0 stack= before 2: (d5) if r0 s<= 0x0 goto pc+1
mark_precise: frame0: regs=r0 stack= before 1: (b7) r0 = 0
6: R0_w=0
First off, note that in `6: R0_w=0` instruction index corresponds to the
next instruction, not to the conditional jump instruction itself, which
is wrong and we'll get to that.
But besides that, the above is a happy case that does work today. Yet,
if it so happens that precision backtracking had to traverse some of the
parent states, this `6: R0_w=0` state output would be missing.
This is due to a quirk of print_verifier_state() routine, which performs
mark_verifier_state_clean(env) at the end. This marks all registers as
"non-scratched", which means that subsequent logic to print *relevant*
registers (that is, "scratched ones") fails and doesn't see anything
relevant to print and skips the output altogether.
print_verifier_state() is used both to print instruction context, but
also to print an **entire** verifier state indiscriminately, e.g.,
during precision backtracking (and in a few other situations, like
during entering or exiting subprogram). Which means if we have to print
entire parent state before getting to printing instruction context
state, instruction context is marked as clean and is omitted.
Long story short, this is definitely not intentional. So we fix this
behavior in this patch by teaching print_verifier_state() to clear
scratch state only if it was used to print instruction state, not the
parent/callback state. This is determined by print_all option, so if
it's not set, we don't clear scratch state. This fixes missing
instruction state for these cases.
As for the mismatched instruction index, we fix that by making sure we
call print_insn_state() early inside check_cond_jmp_op() before we
adjusted insn_idx based on jump branch taken logic. And with that we get
desired correct information:
9: (16) if w4 == 0x1 goto pc+9
mark_precise: frame0: last_idx 9 first_idx 9 subseq_idx -1
mark_precise: frame0: parent state regs=r4 stack=: R2_w=1944 R4_rw=P1 R10=fp0
mark_precise: frame0: last_idx 8 first_idx 0 subseq_idx 9
mark_precise: frame0: regs=r4 stack= before 8: (66) if w4 s> 0x3 goto pc+5
mark_precise: frame0: regs=r4 stack= before 7: (b7) r4 = 1
9: R4=1
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20231011223728.3188086-6-andrii@kernel.org
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Currently the way that verifier prints SCALAR_VALUE register state (and
PTR_TO_PACKET, which can have var_off and ranges info as well) is very
ambiguous.
In the name of brevity we are trying to eliminate "unnecessary" output
of umin/umax, smin/smax, u32_min/u32_max, and s32_min/s32_max values, if
possible. Current rules are that if any of those have their default
value (which for mins is the minimal value of its respective types: 0,
S32_MIN, or S64_MIN, while for maxs it's U32_MAX, S32_MAX, S64_MAX, or
U64_MAX) *OR* if there is another min/max value that as matching value.
E.g., if smin=100 and umin=100, we'll emit only umin=10, omitting smin
altogether. This approach has a few problems, being both ambiguous and
sort-of incorrect in some cases.
Ambiguity is due to missing value could be either default value or value
of umin/umax or smin/smax. This is especially confusing when we mix
signed and unsigned ranges. Quite often, umin=0 and smin=0, and so we'll
have only `umin=0` leaving anyone reading verifier log to guess whether
smin is actually 0 or it's actually -9223372036854775808 (S64_MIN). And
often times it's important to know, especially when debugging tricky
issues.
"Sort-of incorrectness" comes from mixing negative and positive values.
E.g., if umin is some large positive number, it can be equal to smin
which is, interpreted as signed value, is actually some negative value.
Currently, that smin will be omitted and only umin will be emitted with
a large positive value, giving an impression that smin is also positive.
Anyway, ambiguity is the biggest issue making it impossible to have an
exact understanding of register state, preventing any sort of automated
testing of verifier state based on verifier log. This patch is
attempting to rectify the situation by removing ambiguity, while
minimizing the verboseness of register state output.
The rules are straightforward:
- if some of the values are missing, then it definitely has a default
value. I.e., `umin=0` means that umin is zero, but smin is actually
S64_MIN;
- all the various boundaries that happen to have the same value are
emitted in one equality separated sequence. E.g., if umin and smin are
both 100, we'll emit `smin=umin=100`, making this explicit;
- we do not mix negative and positive values together, and even if
they happen to have the same bit-level value, they will be emitted
separately with proper sign. I.e., if both umax and smax happen to be
0xffffffffffffffff, we'll emit them both separately as
`smax=-1,umax=18446744073709551615`;
- in the name of a bit more uniformity and consistency,
{u32,s32}_{min,max} are renamed to {s,u}{min,max}32, which seems to
improve readability.
The above means that in case of all 4 ranges being, say, [50, 100] range,
we'd previously see hugely ambiguous:
R1=scalar(umin=50,umax=100)
Now, we'll be more explicit:
R1=scalar(smin=umin=smin32=umin32=50,smax=umax=smax32=umax32=100)
This is slightly more verbose, but distinct from the case when we don't
know anything about signed boundaries and 32-bit boundaries, which under
new rules will match the old case:
R1=scalar(umin=50,umax=100)
Also, in the name of simplicity of implementation and consistency, order
for {s,u}32_{min,max} are emitted *before* var_off. Previously they were
emitted afterwards, for unclear reasons.
This patch also includes a few fixes to selftests that expect exact
register state to accommodate slight changes to verifier format. You can
see that the changes are pretty minimal in common cases.
Note, the special case when SCALAR_VALUE register is a known constant
isn't changed, we'll emit constant value once, interpreted as signed
value.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20231011223728.3188086-5-andrii@kernel.org
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The PSI trigger code is now making a distinction between privileged and
unprivileged triggers, after the following commit:
65457b74aa94 ("sched/psi: Rename existing poll members in preparation")
But some comments have not been modified along with the code, so they
need to be updated.
This will help readers better understand the code.
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Peter Ziljstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/202310161920399921184@zte.com.cn
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Add the necessary structure to support custom private-data per
posix-clock user.
The previous implementation of posix-clock assumed all file open
instances need access to the same clock structure on private_data.
The need for individual data structures per file open instance has been
identified when developing support for multiple timestamp event queue
users for ptp_clock.
Signed-off-by: Xabier Marquiegui <reibax@gmail.com>
Suggested-by: Richard Cochran <richardcochran@gmail.com>
Suggested-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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When entering kdb/kgdb on a kernel panic, it was be observed that the
console isn't flushed before the `kdb` prompt came up. Specifically,
when using the buddy lockup detector on arm64 and running:
echo HARDLOCKUP > /sys/kernel/debug/provoke-crash/DIRECT
I could see:
[ 26.161099] lkdtm: Performing direct entry HARDLOCKUP
[ 32.499881] watchdog: Watchdog detected hard LOCKUP on cpu 6
[ 32.552865] Sending NMI from CPU 5 to CPUs 6:
[ 32.557359] NMI backtrace for cpu 6
... [backtrace for cpu 6] ...
[ 32.558353] NMI backtrace for cpu 5
... [backtrace for cpu 5] ...
[ 32.867471] Sending NMI from CPU 5 to CPUs 0-4,7:
[ 32.872321] NMI backtrace forP cpuANC: Hard LOCKUP
Entering kdb (current=..., pid 0) on processor 5 due to Keyboard Entry
[5]kdb>
As you can see, backtraces for the other CPUs start printing and get
interleaved with the kdb PANIC print.
Let's replicate the commands to flush the console in the kdb panic
entry point to avoid this.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20230822131945.1.I5b460ae8f954e4c4f628a373d6e74713c06dd26f@changeid
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"Two EEVDF fixes"
* tag 'sched-urgent-2023-10-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/eevdf: Fix pick_eevdf()
sched/eevdf: Fix min_deadline heap integrity
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This patch adds kfuncs bpf_iter_task_vma_{new,next,destroy} which allow
creation and manipulation of struct bpf_iter_task_vma in open-coded
iterator style. BPF programs can use these kfuncs directly or through
bpf_for_each macro for natural-looking iteration of all task vmas.
The implementation borrows heavily from bpf_find_vma helper's locking -
differing only in that it holds the mmap_read lock for all iterations
while the helper only executes its provided callback on a maximum of 1
vma. Aside from locking, struct vma_iterator and vma_next do all the
heavy lifting.
A pointer to an inner data struct, struct bpf_iter_task_vma_data, is the
only field in struct bpf_iter_task_vma. This is because the inner data
struct contains a struct vma_iterator (not ptr), whose size is likely to
change under us. If bpf_iter_task_vma_kern contained vma_iterator directly
such a change would require change in opaque bpf_iter_task_vma struct's
size. So better to allocate vma_iterator using BPF allocator, and since
that alloc must already succeed, might as well allocate all iter fields,
thereby freezing struct bpf_iter_task_vma size.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231013204426.1074286-4-davemarchevsky@fb.com
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Commit 6018e1f407cc ("bpf: implement numbers iterator") added the
BTF_TYPE_EMIT line that this patch is modifying. The struct btf_iter_num
doesn't exist, so only a forward declaration is emitted in BTF:
FWD 'btf_iter_num' fwd_kind=struct
That commit was probably hoping to ensure that struct bpf_iter_num is
emitted in vmlinux BTF. A previous version of this patch changed the
line to emit the correct type, but Yonghong confirmed that it would
definitely be emitted regardless in [0], so this patch simply removes
the line.
This isn't marked "Fixes" because the extraneous btf_iter_num FWD wasn't
causing any issues that I noticed, aside from mild confusion when I
looked through the code.
[0]: https://lore.kernel.org/bpf/25d08207-43e6-36a8-5e0f-47a913d4cda5@linux.dev/
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231013204426.1074286-2-davemarchevsky@fb.com
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linux-rt-devel tree contains a patch (b1773eac3f29c ("sched: Add support
for lazy preemption")) that adds an extra member to struct trace_entry.
This causes the offset of args field in struct trace_event_raw_sys_enter
be different from the one in struct syscall_trace_enter:
struct trace_event_raw_sys_enter {
struct trace_entry ent; /* 0 12 */
/* XXX last struct has 3 bytes of padding */
/* XXX 4 bytes hole, try to pack */
long int id; /* 16 8 */
long unsigned int args[6]; /* 24 48 */
/* --- cacheline 1 boundary (64 bytes) was 8 bytes ago --- */
char __data[]; /* 72 0 */
/* size: 72, cachelines: 2, members: 4 */
/* sum members: 68, holes: 1, sum holes: 4 */
/* paddings: 1, sum paddings: 3 */
/* last cacheline: 8 bytes */
};
struct syscall_trace_enter {
struct trace_entry ent; /* 0 12 */
/* XXX last struct has 3 bytes of padding */
int nr; /* 12 4 */
long unsigned int args[]; /* 16 0 */
/* size: 16, cachelines: 1, members: 3 */
/* paddings: 1, sum paddings: 3 */
/* last cacheline: 16 bytes */
};
This, in turn, causes perf_event_set_bpf_prog() fail while running bpf
test_profiler testcase because max_ctx_offset is calculated based on the
former struct, while off on the latter:
10488 if (is_tracepoint || is_syscall_tp) {
10489 int off = trace_event_get_offsets(event->tp_event);
10490
10491 if (prog->aux->max_ctx_offset > off)
10492 return -EACCES;
10493 }
What bpf program is actually getting is a pointer to struct
syscall_tp_t, defined in kernel/trace/trace_syscalls.c. This patch fixes
the problem by aligning struct syscall_tp_t with struct
syscall_trace_(enter|exit) and changing the tests to use these structs
to dereference context.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20231013054219.172920-1-asavkov@redhat.com
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An io_uring openat operation can update an audit reference count
from multiple threads resulting in the call trace below.
A call to io_uring_submit() with a single openat op with a flag of
IOSQE_ASYNC results in the following reference count updates.
These first part of the system call performs two increments that do not race.
do_syscall_64()
__do_sys_io_uring_enter()
io_submit_sqes()
io_openat_prep()
__io_openat_prep()
getname()
getname_flags() /* update 1 (increment) */
__audit_getname() /* update 2 (increment) */
The openat op is queued to an io_uring worker thread which starts the
opportunity for a race. The system call exit performs one decrement.
do_syscall_64()
syscall_exit_to_user_mode()
syscall_exit_to_user_mode_prepare()
__audit_syscall_exit()
audit_reset_context()
putname() /* update 3 (decrement) */
The io_uring worker thread performs one increment and two decrements.
These updates can race with the system call decrement.
io_wqe_worker()
io_worker_handle_work()
io_wq_submit_work()
io_issue_sqe()
io_openat()
io_openat2()
do_filp_open()
path_openat()
__audit_inode() /* update 4 (increment) */
putname() /* update 5 (decrement) */
__audit_uring_exit()
audit_reset_context()
putname() /* update 6 (decrement) */
The fix is to change the refcnt member of struct audit_names
from int to atomic_t.
kernel BUG at fs/namei.c:262!
Call Trace:
...
? putname+0x68/0x70
audit_reset_context.part.0.constprop.0+0xe1/0x300
__audit_uring_exit+0xda/0x1c0
io_issue_sqe+0x1f3/0x450
? lock_timer_base+0x3b/0xd0
io_wq_submit_work+0x8d/0x2b0
? __try_to_del_timer_sync+0x67/0xa0
io_worker_handle_work+0x17c/0x2b0
io_wqe_worker+0x10a/0x350
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/lkml/MW2PR2101MB1033FFF044A258F84AEAA584F1C9A@MW2PR2101MB1033.namprd21.prod.outlook.com/
Fixes: 5bd2182d58e9 ("audit,io_uring,io-wq: add some basic audit support to io_uring")
Signed-off-by: Dan Clash <daclash@linux.microsoft.com>
Link: https://lore.kernel.org/r/20231012215518.GA4048@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Acceleration in SRCU happens on enqueue time for each new callback. This
operation is expected not to fail and therefore any similar attempt
from other places shouldn't find any remaining callbacks to accelerate.
Moreover accelerations performed beyond enqueue time are error prone
because rcu_seq_snap() then may return the snapshot for a new grace
period that is not going to be started.
Remove these dangerous and needless accelerations and introduce instead
assertions reporting leaking unaccelerated callbacks beyond enqueue
time.
Co-developed-by: Yong He <alexyonghe@tencent.com>
Signed-off-by: Yong He <alexyonghe@tencent.com>
Co-developed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Co-developed-by: Neeraj upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Neeraj upadhyay <Neeraj.Upadhyay@amd.com>
Reviewed-by: Like Xu <likexu@tencent.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
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irq_init_generic_chip() only sets the name for the first chip type, which
leads to empty names for other chip types. Eventually, these names will be
shown as "-" /proc/interrupts.
Set the name for all chip types by default.
Signed-off-by: Keguang Zhang <keguang.zhang@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230925121734.93017-1-keguang.zhang@gmail.com
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The PELT acronym definition can be found right at the top of
kernel/sched/pelt.c (of course), but it cannot be found through use of
grep -r PELT kernel/sched/
Add the acronym "(PELT)" after "Per Entity Load Tracking" at the top of
the source file.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20231012125824.1260774-1-mathieu.desnoyers@efficios.com
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Kuyo reported sporadic failures on a sched_setaffinity() vs CPU
hotplug stress-test -- notably affine_move_task() remains stuck in
wait_for_completion(), leading to a hung-task detector warning.
Specifically, it was reported that stop_one_cpu_nowait(.fn =
migration_cpu_stop) returns false -- this stopper is responsible for
the matching complete().
The race scenario is:
CPU0 CPU1
// doing _cpu_down()
__set_cpus_allowed_ptr()
task_rq_lock();
takedown_cpu()
stop_machine_cpuslocked(take_cpu_down..)
<PREEMPT: cpu_stopper_thread()
MULTI_STOP_PREPARE
...
__set_cpus_allowed_ptr_locked()
affine_move_task()
task_rq_unlock();
<PREEMPT: cpu_stopper_thread()\>
ack_state()
MULTI_STOP_RUN
take_cpu_down()
__cpu_disable();
stop_machine_park();
stopper->enabled = false;
/>
/>
stop_one_cpu_nowait(.fn = migration_cpu_stop);
if (stopper->enabled) // false!!!
That is, by doing stop_one_cpu_nowait() after dropping rq-lock, the
stopper thread gets a chance to preempt and allows the cpu-down for
the target CPU to complete.
OTOH, since stop_one_cpu_nowait() / cpu_stop_queue_work() needs to
issue a wakeup, it must not be ran under the scheduler locks.
Solve this apparent contradiction by keeping preemption disabled over
the unlock + queue_stopper combination:
preempt_disable();
task_rq_unlock(...);
if (!stop_pending)
stop_one_cpu_nowait(...)
preempt_enable();
This respects the lock ordering contraints while still avoiding the
above race. That is, if we find the CPU is online under rq-lock, the
targeted stop_one_cpu_nowait() must succeed.
Apply this pattern to all similar stop_one_cpu_nowait() invocations.
Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()")
Reported-by: "Kuyo Chang (張建文)" <Kuyo.Chang@mediatek.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: "Kuyo Chang (張建文)" <Kuyo.Chang@mediatek.com>
Link: https://lkml.kernel.org/r/20231010200442.GA16515@noisy.programming.kicks-ass.net
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|
We could bail out early when psi was disabled.
Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Link: https://lore.kernel.org/r/20230926115722.467833-1-haifeng.xu@shopee.com
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
- In cgroup1, the `tasks` file could have duplicate pids which can
trigger a warning in seq_file. Fix it by removing duplicate items
after sorting
- Comment update
* tag 'cgroup-for-6.6-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: Fix incorrect css_set_rwsem reference in comment
cgroup: Remove duplicates in cgroup v1 tasks file
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fixes from Tejun Heo:
- Fix access-after-free in pwq allocation error path
- Implicitly ordered unbound workqueues should lose the implicit
ordering if an attribute change which isn't compatible with ordered
operation is requested. However, attribute changes requested through
the sysfs interface weren't doing that leaving no way to override the
implicit ordering through the sysfs interface. Fix it.
- Other doc and misc updates
* tag 'wq-for-6.6-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: fix -Wformat-truncation in create_worker
workqueue: Override implicit ordered attribute in workqueue_apply_unbound_cpumask()
workqueue: Use the kmem_cache_free() instead of kfree() to release pwq
workqueue: doc: Fix function and sysfs path errors
workqueue: Fix UAF report by KASAN in pwq_release_workfn()
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Cross-merge networking fixes after downstream PR.
No conflicts.
Adjacent changes:
kernel/bpf/verifier.c
829955981c55 ("bpf: Fix verifier log for async callback return values")
a923819fb2c5 ("bpf: Treat first argument as return value for bpf_throw")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Paolo Abeni:
"Including fixes from CAN and BPF.
We have a regression in TC currently under investigation, otherwise
the things that stand off most are probably the TCP and AF_PACKET
fixes, with both issues coming from 6.5.
Previous releases - regressions:
- af_packet: fix fortified memcpy() without flex array.
- tcp: fix crashes trying to free half-baked MTU probes
- xdp: fix zero-size allocation warning in xskq_create()
- can: sja1000: always restart the tx queue after an overrun
- eth: mlx5e: again mutually exclude RX-FCS and RX-port-timestamp
- eth: nfp: avoid rmmod nfp crash issues
- eth: octeontx2-pf: fix page pool frag allocation warning
Previous releases - always broken:
- mctp: perform route lookups under a RCU read-side lock
- bpf: s390: fix clobbering the caller's backchain in the trampoline
- phy: lynx-28g: cancel the CDR check work item on the remove path
- dsa: qca8k: fix qca8k driver for Turris 1.x
- eth: ravb: fix use-after-free issue in ravb_tx_timeout_work()
- eth: ixgbe: fix crash with empty VF macvlan list"
* tag 'net-6.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (54 commits)
rswitch: Fix imbalance phy_power_off() calling
rswitch: Fix renesas_eth_sw_remove() implementation
octeontx2-pf: Fix page pool frag allocation warning
nfc: nci: assert requested protocol is valid
af_packet: Fix fortified memcpy() without flex array.
net: tcp: fix crashes trying to free half-baked MTU probes
net/smc: Fix pos miscalculation in statistics
nfp: flower: avoid rmmod nfp crash issues
net: usb: dm9601: fix uninitialized variable use in dm9601_mdio_read
ethtool: Fix mod state of verbose no_mask bitset
net: nfc: fix races in nfc_llcp_sock_get() and nfc_llcp_sock_get_sn()
mctp: perform route lookups under a RCU read-side lock
net: skbuff: fix kernel-doc typos
s390/bpf: Fix unwinding past the trampoline
s390/bpf: Fix clobbering the caller's backchain in the trampoline
net/mlx5e: Again mutually exclude RX-FCS and RX-port-timestamp
net/smc: Fix dependency of SMC on ISM
ixgbe: fix crash with empty VF macvlan list
net/mlx5e: macsec: use update_pn flag instead of PN comparation
net: phy: mscc: macsec: reject PN update requests
...
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Compiling with W=1 emitted the following warning
(Compiler: gcc (x86-64, ver. 13.2.1, .config: result of make allyesconfig,
"Treat warnings as errors" turned off):
kernel/workqueue.c:2188:54: warning: ‘%d’ directive output may be
truncated writing between 1 and 10 bytes into a region of size
between 5 and 14 [-Wformat-truncation=]
kernel/workqueue.c:2188:50: note: directive argument in the range
[0, 2147483647]
kernel/workqueue.c:2188:17: note: ‘snprintf’ output between 4 and 23 bytes
into a destination of size 16
setting "id_buf" to size 23 will silence the warning, since GCC
determines snprintf's output to be max. 23 bytes in line 2188.
Please let me know if there are any mistakes in my patch!
Signed-off-by: Lucy Mielke <lucymielke@icloud.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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|
workqueue_apply_unbound_cpumask()
Commit 5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1
to be ordered") enabled implicit ordered attribute to be added to
WQ_UNBOUND workqueues with max_active of 1. This prevented the changing
of attributes to these workqueues leading to fix commit 0a94efb5acbb
("workqueue: implicit ordered attribute should be overridable").
However, workqueue_apply_unbound_cpumask() was not updated at that time.
So sysfs changes to wq_unbound_cpumask has no effect on WQ_UNBOUND
workqueues with implicit ordered attribute. Since not all WQ_UNBOUND
workqueues are visible on sysfs, we are not able to make all the
necessary cpumask changes even if we iterates all the workqueue cpumasks
in sysfs and changing them one by one.
Fix this problem by applying the corresponding change made
to apply_workqueue_attrs_locked() in the fix commit to
workqueue_apply_unbound_cpumask().
Fixes: 5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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compiler-warning
On an allyesconfig, with "treat warnings as errors" unset, GCC emits
these warnings:
kernel/locking/lockdep_proc.c:438:32: Warning: Format specifier '%lld' may
be truncated when writing 1 to 17 bytes into a region
of size 15 [-Wformat-truncation=]
kernel/locking/lockdep_proc.c:438:31: Note: Format directive argument is
in the range [-9223372036854775, 9223372036854775]
kernel/locking/lockdep_proc.c:438:9: Note: 'snprintf' has output
between 5 and 22 bytes into a target of size 15
In seq_time(), the longest s64 is "-9223372036854775808"-ish, which
converted to the fixed-point float format is "-9223372036854775.80": 21 bytes,
plus termination is another byte: 22. Therefore, a larger buffer size
of 22 is needed here - not 15. The code was safe due to the snprintf().
Fix it.
Signed-off-by: Lucy Mielke <lucymielke@icloud.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/ZSfOEHRkZAWaQr3U@fedora.fritz.box
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Currently, the kfree() be used for pwq objects allocated with
kmem_cache_alloc() in alloc_and_link_pwqs(), this isn't wrong.
but usually, use "trace_kmem_cache_alloc/trace_kmem_cache_free"
to track memory allocation and free. this commit therefore use
kmem_cache_free() instead of kfree() in alloc_and_link_pwqs()
and also consistent with release of the pwq in rcu_free_pwq().
Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Namhyung reported that bd2756811766 ("perf: Rewrite core context handling")
regresses context switch overhead when perf-cgroup is in use together
with 'slow' PMUs like uncore.
Specifically, perf_cgroup_switch()'s perf_ctx_disable() /
ctx_sched_out() etc.. all iterate the full list of active PMUs for
that CPU, even if they don't have cgroup events.
Previously there was cgrp_cpuctx_list which linked the relevant PMUs
together, but that got lost in the rework. Instead of re-instruducing
a similar list, let the perf_event_pmu_context iteration skip those
that do not have cgroup events. This avoids growing multiple versions
of the perf_event_pmu_context iteration.
Measured performance (on a slightly different patch):
Before)
$ taskset -c 0 ./perf bench sched pipe -l 10000 -G AAA,BBB
# Running 'sched/pipe' benchmark:
# Executed 10000 pipe operations between two processes
Total time: 0.901 [sec]
90.128700 usecs/op
11095 ops/sec
After)
$ taskset -c 0 ./perf bench sched pipe -l 10000 -G AAA,BBB
# Running 'sched/pipe' benchmark:
# Executed 10000 pipe operations between two processes
Total time: 0.065 [sec]
6.560100 usecs/op
152436 ops/sec
Fixes: bd2756811766 ("perf: Rewrite core context handling")
Reported-by: Namhyung Kim <namhyung@kernel.org>
Debugged-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20231009210425.GC6307@noisy.programming.kicks-ass.net
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While reworking the x86 topology code Thomas tripped over creating a 'DIE' domain
for the package mask. :-)
Since these names are CONFIG_SCHED_DEBUG=y only, rename them to make the
name less ambiguous.
[ Shrikanth Hegde: rename on s390 as well. ]
[ Valentin Schneider: also rename it in the comments. ]
[ mingo: port to recent kernels & find all remaining occurances. ]
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Valentin Schneider <vschneid@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20230712141056.GI3100107@hirez.programming.kicks-ass.net
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|
These hooks allows intercepting connect(), getsockname(),
getpeername(), sendmsg() and recvmsg() for unix sockets. The unix
socket hooks get write access to the address length because the
address length is not fixed when dealing with unix sockets and
needs to be modified when a unix socket address is modified by
the hook. Because abstract socket unix addresses start with a
NUL byte, we cannot recalculate the socket address in kernelspace
after running the hook by calculating the length of the unix socket
path using strlen().
These hooks can be used when users want to multiplex syscall to a
single unix socket to multiple different processes behind the scenes
by redirecting the connect() and other syscalls to process specific
sockets.
We do not implement support for intercepting bind() because when
using bind() with unix sockets with a pathname address, this creates
an inode in the filesystem which must be cleaned up. If we rewrite
the address, the user might try to clean up the wrong file, leaking
the socket in the filesystem where it is never cleaned up. Until we
figure out a solution for this (and a use case for intercepting bind()),
we opt to not allow rewriting the sockaddr in bind() calls.
We also implement recvmsg() support for connected streams so that
after a connect() that is modified by a sockaddr hook, any corresponding
recmvsg() on the connected socket can also be modified to make the
connected program think it is connected to the "intended" remote.
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
Link: https://lore.kernel.org/r/20231011185113.140426-5-daan.j.demeyer@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
|
|
As prep for adding unix socket support to the cgroup sockaddr hooks,
let's add a kfunc bpf_sock_addr_set_sun_path() that allows modifying a unix
sockaddr from bpf. While this is already possible for AF_INET and AF_INET6,
we'll need this kfunc when we add unix socket support since modifying the
address for those requires modifying both the address and the sockaddr
length.
Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
Link: https://lore.kernel.org/r/20231011185113.140426-4-daan.j.demeyer@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
|
|
As prep for adding unix socket support to the cgroup sockaddr hooks,
let's propagate the sockaddr length back to the caller after running
a bpf cgroup sockaddr hook program. While not important for AF_INET or
AF_INET6, the sockaddr length is important when working with AF_UNIX
sockaddrs as the size of the sockaddr cannot be determined just from the
address family or the sockaddr's contents.
__cgroup_bpf_run_filter_sock_addr() is modified to take the uaddrlen as
an input/output argument. After running the program, the modified sockaddr
length is stored in the uaddrlen pointer.
Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com>
Link: https://lore.kernel.org/r/20231011185113.140426-3-daan.j.demeyer@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
|
|
The 'update_total' parameter of update_triggers() is always true after the
previous commit:
80cc1d1d5ee3 ("sched/psi: Avoid updating PSI triggers and ->rtpoll_total when there are no state changes")
If the 'changed_states & group->rtpoll_states' condition is true,
'new_stall' in update_triggers() will be true, and then 'update_total'
should also be true.
So update_total is redundant - remove it.
[ mingo: Changelog updates ]
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Peter Ziljstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/202310101645437859599@zte.com.cn
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|
state changes
When psimon wakes up and there are no state changes for ->rtpoll_states,
it's unnecessary to update triggers and ->rtpoll_total because the pressures
being monitored by the user have not changed.
This will help to slightly reduce unnecessary computations of PSI.
[ mingo: Changelog updates ]
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Peter Ziljstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/202310101641075436843@zte.com.cn
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git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk regression fix from Petr Mladek:
- Avoid unnecessary wait and try to flush messages before checking
pending ones
* tag 'printk-for-6.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk: flush consoles before checking progress
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Enable unprivileged sandboxes to create their own binfmt_misc mounts.
This is based on Laurent's work in [1] but has been significantly
reworked to fix various issues we identified in earlier versions.
While binfmt_misc can currently only be mounted in the initial user
namespace, binary types registered in this binfmt_misc instance are
available to all sandboxes (Either by having them installed in the
sandbox or by registering the binary type with the F flag causing the
interpreter to be opened right away). So binfmt_misc binary types are
already delegated to sandboxes implicitly.
However, while a sandbox has access to all registered binary types in
binfmt_misc a sandbox cannot currently register its own binary types
in binfmt_misc. This has prevented various use-cases some of which were
already outlined in [1] but we have a range of issues associated with
this (cf. [3]-[5] below which are just a small sample).
Extend binfmt_misc to be mountable in non-initial user namespaces.
Similar to other filesystem such as nfsd, mqueue, and sunrpc we use
keyed superblock management. The key determines whether we need to
create a new superblock or can reuse an already existing one. We use the
user namespace of the mount as key. This means a new binfmt_misc
superblock is created once per user namespace creation. Subsequent
mounts of binfmt_misc in the same user namespace will mount the same
binfmt_misc instance. We explicitly do not create a new binfmt_misc
superblock on every binfmt_misc mount as the semantics for
load_misc_binary() line up with the keying model. This also allows us to
retrieve the relevant binfmt_misc instance based on the caller's user
namespace which can be done in a simple (bounded to 32 levels) loop.
Similar to the current binfmt_misc semantics allowing access to the
binary types in the initial binfmt_misc instance we do allow sandboxes
access to their parent's binfmt_misc mounts if they do not have created
a separate binfmt_misc instance.
Overall, this will unblock the use-cases mentioned below and in general
will also allow to support and harden execution of another
architecture's binaries in tight sandboxes. For instance, using the
unshare binary it possible to start a chroot of another architecture and
configure the binfmt_misc interpreter without being root to run the
binaries in this chroot and without requiring the host to modify its
binary type handlers.
Henning had already posted a few experiments in the cover letter at [1].
But here's an additional example where an unprivileged container
registers qemu-user-static binary handlers for various binary types in
its separate binfmt_misc mount and is then seamlessly able to start
containers with a different architecture without affecting the host:
root [lxc monitor] /var/snap/lxd/common/lxd/containers f1
1000000 \_ /sbin/init
1000000 \_ /lib/systemd/systemd-journald
1000000 \_ /lib/systemd/systemd-udevd
1000100 \_ /lib/systemd/systemd-networkd
1000101 \_ /lib/systemd/systemd-resolved
1000000 \_ /usr/sbin/cron -f
1000103 \_ /usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation --syslog-only
1000000 \_ /usr/bin/python3 /usr/bin/networkd-dispatcher --run-startup-triggers
1000104 \_ /usr/sbin/rsyslogd -n -iNONE
1000000 \_ /lib/systemd/systemd-logind
1000000 \_ /sbin/agetty -o -p -- \u --noclear --keep-baud console 115200,38400,9600 vt220
1000107 \_ dnsmasq --conf-file=/dev/null -u lxc-dnsmasq --strict-order --bind-interfaces --pid-file=/run/lxc/dnsmasq.pid --liste
1000000 \_ [lxc monitor] /var/lib/lxc f1-s390x
1100000 \_ /usr/bin/qemu-s390x-static /sbin/init
1100000 \_ /usr/bin/qemu-s390x-static /lib/systemd/systemd-journald
1100000 \_ /usr/bin/qemu-s390x-static /usr/sbin/cron -f
1100103 \_ /usr/bin/qemu-s390x-static /usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-ac
1100000 \_ /usr/bin/qemu-s390x-static /usr/bin/python3 /usr/bin/networkd-dispatcher --run-startup-triggers
1100104 \_ /usr/bin/qemu-s390x-static /usr/sbin/rsyslogd -n -iNONE
1100000 \_ /usr/bin/qemu-s390x-static /lib/systemd/systemd-logind
1100000 \_ /usr/bin/qemu-s390x-static /sbin/agetty -o -p -- \u --noclear --keep-baud console 115200,38400,9600 vt220
1100000 \_ /usr/bin/qemu-s390x-static /sbin/agetty -o -p -- \u --noclear --keep-baud pts/0 115200,38400,9600 vt220
1100000 \_ /usr/bin/qemu-s390x-static /sbin/agetty -o -p -- \u --noclear --keep-baud pts/1 115200,38400,9600 vt220
1100000 \_ /usr/bin/qemu-s390x-static /sbin/agetty -o -p -- \u --noclear --keep-baud pts/2 115200,38400,9600 vt220
1100000 \_ /usr/bin/qemu-s390x-static /sbin/agetty -o -p -- \u --noclear --keep-baud pts/3 115200,38400,9600 vt220
1100000 \_ /usr/bin/qemu-s390x-static /lib/systemd/systemd-udevd
[1]: https://lore.kernel.org/all/20191216091220.465626-1-laurent@vivier.eu
[2]: https://discuss.linuxcontainers.org/t/binfmt-misc-permission-denied
[3]: https://discuss.linuxcontainers.org/t/lxd-binfmt-support-for-qemu-static-interpreters
[4]: https://discuss.linuxcontainers.org/t/3-1-0-binfmt-support-service-in-unprivileged-guest-requires-write-access-on-hosts-proc-sys-fs-binfmt-misc
[5]: https://discuss.linuxcontainers.org/t/qemu-user-static-not-working-4-11
Link: https://lore.kernel.org/r/20191216091220.465626-2-laurent@vivier.eu (origin)
Link: https://lore.kernel.org/r/20211028103114.2849140-2-brauner@kernel.org (v1)
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Jann Horn <jannh@google.com>
Cc: Henning Schild <henning.schild@siemens.com>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Laurent Vivier <laurent@vivier.eu>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
/* v2 */
- Serge Hallyn <serge@hallyn.com>:
- Use GFP_KERNEL_ACCOUNT for userspace triggered allocations when a
new binary type handler is registered.
- Christian Brauner <christian.brauner@ubuntu.com>:
- Switch authorship to me. I refused to do that earlier even though
Laurent said I should do so because I think it's genuinely bad form.
But by now I have changed so many things that it'd be unfair to
blame Laurent for any potential bugs in here.
- Add more comments that explain what's going on.
- Rename functions while changing them to better reflect what they are
doing to make the code easier to understand.
- In the first version when a specific binary type handler was removed
either through a write to the entry's file or all binary type
handlers were removed by a write to the binfmt_misc mount's status
file all cleanup work happened during inode eviction.
That includes removal of the relevant entries from entry list. While
that works fine I disliked that model after thinking about it for a
bit. Because it means that there was a window were someone has
already removed a or all binary handlers but they could still be
safely reached from load_misc_binary() when it has managed to take
the read_lock() on the entries list while inode eviction was already
happening. Again, that perfectly benign but it's cleaner to remove
the binary handler from the list immediately meaning that ones the
write to then entry's file or the binfmt_misc status file returns
the binary type cannot be executed anymore. That gives stronger
guarantees to the user.
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There is a typo so this checks the wrong variable. "chains" plural vs
"chain" singular. We already know that "chains" is non-zero.
Fixes: 7f993623e9eb ("locktorture: Add call_rcu_chains module parameter")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
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pr_flush() does not guarantee that all messages would really get flushed
to the console. The best it could do is to wait with a given timeout.[*]
The current interval 100ms for checking the progress might seem too
long in some situations. For example, such delays are not appreciated
during suspend and resume especially when the consoles have been flushed
"long" time before the check.
On the other hand, the sleeping wait might be useful in other situations.
Especially, it would allow flushing the messages using printk kthreads
on the same CPU[*].
Use msleep(1) as a compromise.
Also measure the time using jiffies. msleep() does not guarantee
precise wakeup after the given delay. It might be much longer,
especially for times < 20s. See Documentation/timers/timers-howto.rst
for more details.
Note that msecs_to_jiffies() already translates a negative value into
an infinite timeout.
[*] console_unlock() does not guarantee flushing the consoles since
the commit dbdda842fe96f893 ("printk: Add console owner and waiter
logic to load balance console writes").
It would be possible to guarantee it another way. For example,
the spinning might be enabled only when the console_lock has been
taken via console_trylock().
But the load balancing is helpful. And more importantly, the flush
with a timeout has been added as a preparation step for introducing
printk kthreads.
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/r/20231006082151.6969-3-pmladek@suse.com
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removed
There is a comment that refers to cpu_load, however, this cpu_load was
removed with:
55627e3cd22c ("sched/core: Remove rq->cpu_load[]")
... back in 2019. The comment does not make sense with respect to this
removed array, so remove the comment.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231010155744.1381065-1-colin.i.king@gmail.com
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VMAs are skipped if there is no recent fault activity but this represents
a chicken-and-egg problem as there may be no fault activity if the PTEs
are never updated to trap NUMA hints. There is an indirect reliance on
scanning to be forced early in the lifetime of a task but this may fail
to detect changes in phase behaviour. Force inactive VMAs to be scanned
when all other eligible VMAs have been updated within the same scan
sequence.
Test results in general look good with some changes in performance, both
negative and positive, depending on whether the additional scanning and
faulting was beneficial or not to the workload. The autonuma benchmark
workload NUMA01_THREADLOCAL was picked for closer examination. The workload
creates two processes with numerous threads and thread-local storage that
is zero-filled in a loop. It exercises the corner case where unrelated
threads may skip VMAs that are thread-local to another thread and still
has some VMAs that inactive while the workload executes.
The VMA skipping activity frequency with and without the patch:
6.6.0-rc2-sched-numabtrace-v1
=============================
649 reason=scan_delay
9,094 reason=unsuitable
48,915 reason=shared_ro
143,919 reason=inaccessible
193,050 reason=pid_inactive
6.6.0-rc2-sched-numabselective-v1
=============================
146 reason=seq_completed
622 reason=ignore_pid_inactive
624 reason=scan_delay
6,570 reason=unsuitable
16,101 reason=shared_ro
27,608 reason=inaccessible
41,939 reason=pid_inactive
Note that with the patch applied, the PID activity is ignored
(ignore_pid_inactive) to ensure a VMA with some activity is completely
scanned. In addition, a small number of VMAs are scanned when no other
eligible VMA is available during a single scan window (seq_completed).
The number of times a VMA is skipped due to no PID activity from the
scanning task (pid_inactive) drops dramatically. It is expected that
this will increase the number of PTEs updated for NUMA hinting faults
as well as hinting faults but these represent PTEs that would otherwise
have been missed. The tradeoff is scan+fault overhead versus improving
locality due to migration.
On a 2-socket Cascade Lake test machine, the time to complete the
workload is as follows;
6.6.0-rc2 6.6.0-rc2
sched-numabtrace-v1 sched-numabselective-v1
Min elsp-NUMA01_THREADLOCAL 174.22 ( 0.00%) 117.64 ( 32.48%)
Amean elsp-NUMA01_THREADLOCAL 175.68 ( 0.00%) 123.34 * 29.79%*
Stddev elsp-NUMA01_THREADLOCAL 1.20 ( 0.00%) 4.06 (-238.20%)
CoeffVar elsp-NUMA01_THREADLOCAL 0.68 ( 0.00%) 3.29 (-381.70%)
Max elsp-NUMA01_THREADLOCAL 177.18 ( 0.00%) 128.03 ( 27.74%)
The time to complete the workload is reduced by almost 30%:
6.6.0-rc2 6.6.0-rc2
sched-numabtrace-v1 sched-numabselective-v1 /
Duration User 91201.80 63506.64
Duration System 2015.53 1819.78
Duration Elapsed 1234.77 868.37
In this specific case, system CPU time was not increased but it's not
universally true.
From vmstat, the NUMA scanning and fault activity is as follows;
6.6.0-rc2 6.6.0-rc2
sched-numabtrace-v1 sched-numabselective-v1
Ops NUMA base-page range updates 64272.00 26374386.00
Ops NUMA PTE updates 36624.00 55538.00
Ops NUMA PMD updates 54.00 51404.00
Ops NUMA hint faults 15504.00 75786.00
Ops NUMA hint local faults % 14860.00 56763.00
Ops NUMA hint local percent 95.85 74.90
Ops NUMA pages migrated 1629.00 6469222.00
Both the number of PTE updates and hint faults is dramatically
increased. While this is superficially unfortunate, it represents
ranges that were simply skipped without the patch. As a result
of the scanning and hinting faults, many more pages were also
migrated but as the time to completion is reduced, the overhead
is offset by the gain.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Raghavendra K T <raghavendra.kt@amd.com>
Link: https://lore.kernel.org/r/20231010083143.19593-7-mgorman@techsingularity.net
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NUMA Balancing skips VMAs when the current task has not trapped a NUMA
fault within the VMA. If the VMA is skipped then mm->numa_scan_offset
advances and a task that is trapping faults within the VMA may never
fully update PTEs within the VMA.
Force tasks to update PTEs for partially scanned PTEs. The VMA will
be tagged for NUMA hints by some task but this removes some of the
benefit of tracking PID activity within a VMA. A follow-on patch
will mitigate this problem.
The test cases and machines evaluated did not trigger the corner case so
the performance results are neutral with only small changes within the
noise from normal test-to-test variance. However, the next patch makes
the corner case easier to trigger.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Raghavendra K T <raghavendra.kt@amd.com>
Link: https://lore.kernel.org/r/20231010083143.19593-6-mgorman@techsingularity.net
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Fix the various warnings from kernel-doc in kernel/fork.c
Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230824193644.3029141-1-willy@infradead.org
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SRCU callbacks acceleration might fail if the preceding callbacks
advance also fails. This can happen when the following steps are met:
1) The RCU_WAIT_TAIL segment has callbacks (say for gp_num 8) and the
RCU_NEXT_READY_TAIL also has callbacks (say for gp_num 12).
2) The grace period for RCU_WAIT_TAIL is observed as started but not yet
completed so rcu_seq_current() returns 4 + SRCU_STATE_SCAN1 = 5.
3) This value is passed to rcu_segcblist_advance() which can't move
any segment forward and fails.
4) srcu_gp_start_if_needed() still proceeds with callback acceleration.
But then the call to rcu_seq_snap() observes the grace period for the
RCU_WAIT_TAIL segment (gp_num 8) as completed and the subsequent one
for the RCU_NEXT_READY_TAIL segment as started
(ie: 8 + SRCU_STATE_SCAN1 = 9) so it returns a snapshot of the
next grace period, which is 16.
5) The value of 16 is passed to rcu_segcblist_accelerate() but the
freshly enqueued callback in RCU_NEXT_TAIL can't move to
RCU_NEXT_READY_TAIL which already has callbacks for a previous grace
period (gp_num = 12). So acceleration fails.
6) Note in all these steps, srcu_invoke_callbacks() hadn't had a chance
to run srcu_invoke_callbacks().
Then some very bad outcome may happen if the following happens:
7) Some other CPU races and starts the grace period number 16 before the
CPU handling previous steps had a chance. Therefore srcu_gp_start()
isn't called on the latter sdp to fix the acceleration leak from
previous steps with a new pair of call to advance/accelerate.
8) The grace period 16 completes and srcu_invoke_callbacks() is finally
called. All the callbacks from previous grace periods (8 and 12) are
correctly advanced and executed but callbacks in RCU_NEXT_READY_TAIL
still remain. Then rcu_segcblist_accelerate() is called with a
snaphot of 20.
9) Since nothing started the grace period number 20, callbacks stay
unhandled.
This has been reported in real load:
[3144162.608392] INFO: task kworker/136:12:252684 blocked for more
than 122 seconds.
[3144162.615986] Tainted: G O K 5.4.203-1-tlinux4-0011.1 #1
[3144162.623053] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
disables this message.
[3144162.631162] kworker/136:12 D 0 252684 2 0x90004000
[3144162.631189] Workqueue: kvm-irqfd-cleanup irqfd_shutdown [kvm]
[3144162.631192] Call Trace:
[3144162.631202] __schedule+0x2ee/0x660
[3144162.631206] schedule+0x33/0xa0
[3144162.631209] schedule_timeout+0x1c4/0x340
[3144162.631214] ? update_load_avg+0x82/0x660
[3144162.631217] ? raw_spin_rq_lock_nested+0x1f/0x30
[3144162.631218] wait_for_completion+0x119/0x180
[3144162.631220] ? wake_up_q+0x80/0x80
[3144162.631224] __synchronize_srcu.part.19+0x81/0xb0
[3144162.631226] ? __bpf_trace_rcu_utilization+0x10/0x10
[3144162.631227] synchronize_srcu+0x5f/0xc0
[3144162.631236] irqfd_shutdown+0x3c/0xb0 [kvm]
[3144162.631239] ? __schedule+0x2f6/0x660
[3144162.631243] process_one_work+0x19a/0x3a0
[3144162.631244] worker_thread+0x37/0x3a0
[3144162.631247] kthread+0x117/0x140
[3144162.631247] ? process_one_work+0x3a0/0x3a0
[3144162.631248] ? __kthread_cancel_work+0x40/0x40
[3144162.631250] ret_from_fork+0x1f/0x30
Fix this with taking the snapshot for acceleration _before_ the read
of the current grace period number.
The only side effect of this solution is that callbacks advancing happen
then _after_ the full barrier in rcu_seq_snap(). This is not a problem
because that barrier only cares about:
1) Ordering accesses of the update side before call_srcu() so they don't
bleed.
2) See all the accesses prior to the grace period of the current gp_num
The only things callbacks advancing need to be ordered against are
carried by snp locking.
Reported-by: Yong He <alexyonghe@tencent.com>
Co-developed-by:: Yong He <alexyonghe@tencent.com>
Signed-off-by: Yong He <alexyonghe@tencent.com>
Co-developed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Co-developed-by: Neeraj upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Neeraj upadhyay <Neeraj.Upadhyay@amd.com>
Link: http://lore.kernel.org/CANZk6aR+CqZaqmMWrC2eRRPY12qAZnDZLwLnHZbNi=xXMB401g@mail.gmail.com
Fixes: da915ad5cf25 ("srcu: Parallelize callback handling")
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
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