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Adding elf symbol iterator object (and some functions) that follow
open-coded iterator pattern and some functions to ease up iterating
elf object symbols.
The idea is to iterate single symbol section with:
struct elf_sym_iter iter;
struct elf_sym *sym;
if (elf_sym_iter_new(&iter, elf, binary_path, SHT_DYNSYM))
goto error;
while ((sym = elf_sym_iter_next(&iter))) {
...
}
I considered opening the elf inside the iterator and iterate all symbol
sections, but then it gets more complicated wrt user checks for when
the next section is processed.
Plus side is the we don't need 'exit' function, because caller/user is
in charge of that.
The returned iterated symbol object from elf_sym_iter_next function
is placed inside the struct elf_sym_iter, so no extra allocation or
argument is needed.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230809083440.3209381-11-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Adding elf_open/elf_close functions and using it in
elf_find_func_offset_from_file function. It will be
used in following changes to save some common code.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230809083440.3209381-10-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Adding new elf object that will contain elf related functions.
There's no functional change.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230809083440.3209381-9-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Adding new uprobe_multi attach type and link names,
so the functions can resolve the new values.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230809083440.3209381-8-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Adding support for bpf_get_func_ip helper being called from
ebpf program attached by uprobe_multi link.
It returns the ip of the uprobe.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230809083440.3209381-7-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Adding support to specify pid for uprobe_multi link and the uprobes
are created only for task with given pid value.
Using the consumer.filter filter callback for that, so the task gets
filtered during the uprobe installation.
We still need to check the task during runtime in the uprobe handler,
because the handler could get executed if there's another system
wide consumer on the same uprobe (thanks Oleg for the insight).
Cc: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230809083440.3209381-6-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Adding support to specify cookies array for uprobe_multi link.
The cookies array share indexes and length with other uprobe_multi
arrays (offsets/ref_ctr_offsets).
The cookies[i] value defines cookie for i-the uprobe and will be
returned by bpf_get_attach_cookie helper when called from ebpf
program hooked to that specific uprobe.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230809083440.3209381-5-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Adding new multi uprobe link that allows to attach bpf program
to multiple uprobes.
Uprobes to attach are specified via new link_create uprobe_multi
union:
struct {
__aligned_u64 path;
__aligned_u64 offsets;
__aligned_u64 ref_ctr_offsets;
__u32 cnt;
__u32 flags;
} uprobe_multi;
Uprobes are defined for single binary specified in path and multiple
calling sites specified in offsets array with optional reference
counters specified in ref_ctr_offsets array. All specified arrays
have length of 'cnt'.
The 'flags' supports single bit for now that marks the uprobe as
return probe.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230809083440.3209381-4-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Add extra attach_type checks from link_create under
bpf_prog_attach_check_attach_type.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230809083440.3209381-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Switching BPF_F_KPROBE_MULTI_RETURN macro to anonymous enum,
so it'd show up in vmlinux.h. There's not functional change
compared to having this as macro.
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230809083440.3209381-2-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Daniel T. Lee says:
====================
samples/bpf: make BPF programs more libbpf aware
The existing tracing programs have been developed for a considerable
period of time and, as a result, do not properly incorporate the
features of the current libbpf, such as CO-RE. This is evident in
frequent usage of functions like PT_REGS* and the persistence of "hack"
methods using underscore-style bpf_probe_read_kernel from the past.
These programs are far behind the current level of libbpf and can
potentially confuse users.
The kernel has undergone significant changes, and some of these changes
have broken these programs, but on the other hand, more robust APIs have
been developed for increased stableness.
To list some of the kernel changes that this patch set is focusing on,
- symbol mismatch occurs due to compiler optimization [1]
- inline of blk_account_io* breaks BPF kprobe program [2]
- new tracepoints for the block_io_start/done are introduced [3]
- map lookup probes can't be triggered (bpf_disable_instrumentation)[4]
- BPF_KSYSCALL has been introduced to simplify argument fetching [5]
- convert to vmlinux.h and use tp argument structure within it
- make tracing programs to be more CO-RE centric
In this regard, this patch set aims not only to integrate the latest
features of libbpf into BPF programs but also to reduce confusion and
clarify the BPF programs. This will help with the potential confusion
among users and make the programs more intutitive.
[1]: https://github.com/iovisor/bcc/issues/1754
[2]: https://github.com/iovisor/bcc/issues/4261
[3]: commit 5a80bd075f3b ("block: introduce block_io_start/block_io_done tracepoints")
[4]: commit 7c4cd051add3 ("bpf: Fix syscall's stackmap lookup potential deadlock")
[5]: commit 6f5d467d55f0 ("libbpf: improve BPF_KPROBE_SYSCALL macro and rename it to BPF_KSYSCALL")
====================
Link: https://lore.kernel.org/r/20230818090119.477441-1-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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With the introduction of kprobe.multi, it is now possible to attach
multiple kprobes to a single BPF program without the need for multiple
definitions. Additionally, this method supports wildcard-based
matching, allowing for further simplification of BPF programs. In here,
an asterisk (*) wildcard is used to map to all symbols relevant to
spin_{lock|unlock}.
Furthermore, since kprobe.multi handles symbol matching, this commit
eliminates the need for the previous logic of reading the ksym table to
verify the existence of symbols.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20230818090119.477441-10-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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This commit refactors the syscall tracing programs by adopting the
BPF_KSYSCALL macro. This change aims to enhance the clarity and
simplicity of the BPF programs by reducing the complexity of argument
parsing from pt_regs.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20230818090119.477441-9-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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In the commit 7c4cd051add3 ("bpf: Fix syscall's stackmap lookup
potential deadlock"), a potential deadlock issue was addressed, which
resulted in *_map_lookup_elem not triggering BPF programs.
(prior to lookup, bpf_disable_instrumentation() is used)
To resolve the broken map lookup probe using "htab_map_lookup_elem",
this commit introduces an alternative approach. Instead, it utilize
"bpf_map_copy_value" and apply a filter specifically for the hash table
with map_type.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Fixes: 7c4cd051add3 ("bpf: Fix syscall's stackmap lookup potential deadlock")
Link: https://lore.kernel.org/r/20230818090119.477441-8-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Recently, a new tracepoint for the block layer, specifically the
block_io_start/done tracepoints, was introduced in commit 5a80bd075f3b
("block: introduce block_io_start/block_io_done tracepoints").
Previously, the kprobe entry used for this purpose was quite unstable
and inherently broke relevant probes [1]. Now that a stable tracepoint
is available, this commit replaces the bio latency check with it.
One of the changes made during this replacement is the key used for the
hash table. Since 'struct request' cannot be used as a hash key, the
approach taken follows that which was implemented in bcc/biolatency [2].
(uses dev:sector for the key)
[1]: https://github.com/iovisor/bcc/issues/4261
[2]: https://github.com/iovisor/bcc/pull/4691
Fixes: 450b7879e345 ("block: move blk_account_io_{start,done} to blk-mq.c")
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20230818090119.477441-7-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The existing tracing programs have been developed for a considerable
period of time and, as a result, do not properly incorporate the
features of the current libbpf, such as CO-RE. This is evident in
frequent usage of functions like PT_REGS* and the persistence of "hack"
methods using underscore-style bpf_probe_read_kernel from the past.
These programs are far behind the current level of libbpf and can
potentially confuse users. Therefore, this commit aims to convert the
outdated BPF programs to be more CO-RE centric.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20230818090119.477441-6-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Currently, multiple kprobe programs are suffering from symbol mismatch
due to compiler optimization. These optimizations might induce
additional suffix to the symbol name such as '.isra' or '.constprop'.
# egrep ' finish_task_switch| __netif_receive_skb_core' /proc/kallsyms
ffffffff81135e50 t finish_task_switch.isra.0
ffffffff81dd36d0 t __netif_receive_skb_core.constprop.0
ffffffff8205cc0e t finish_task_switch.isra.0.cold
ffffffff820b1aba t __netif_receive_skb_core.constprop.0.cold
To avoid this, this commit replaces the original kprobe section to
kprobe.multi in order to match symbol with wildcard characters. Here,
asterisk is used for avoiding symbol mismatch.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20230818090119.477441-5-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Currently, BPF programs typically have a suffix of .bpf.c. However,
some programs still utilize a mixture of _kern.c suffix alongside the
naming convention. In order to achieve consistency in the naming of
these programs, this commit unifies the inconsistency in the naming
convention of BPF kernel programs.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20230818090119.477441-4-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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This commit replaces separate headers with a single vmlinux.h to
tracing programs. Thanks to that, we no longer need to define the
argument structure for tracing programs directly. For example, argument
for the sched_switch tracpepoint (sched_switch_args) can be replaced
with the vmlinux.h provided trace_event_raw_sched_switch.
Additional defines have been added to the BPF program either directly
or through the inclusion of net_shared.h. Defined values are
PERF_MAX_STACK_DEPTH, IFNAMSIZ constants and __stringify() macro. This
change enables the BPF program to access internal structures with BTF
generated "vmlinux.h" header.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20230818090119.477441-3-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Currently, compiling the bpf programs will result the warning with the
ignored attribute as follows. This commit fixes the warning by adding
cf-protection option.
In file included from ./arch/x86/include/asm/linkage.h:6:
./arch/x86/include/asm/ibt.h:77:8: warning: 'nocf_check' attribute ignored; use -fcf-protection to enable the attribute [-Wignored-attributes]
extern __noendbr u64 ibt_save(bool disable);
^
./arch/x86/include/asm/ibt.h:32:34: note: expanded from macro '__noendbr'
^
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20230818090119.477441-2-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Hou Tao says:
====================
Remove unnecessary synchronizations in cpumap
From: Hou Tao <houtao1@huawei.com>
Hi,
This is the formal patchset to remove unnecessary synchronizations in
cpu-map after address comments and collect Rvb tags from Toke
Høiland-Jørgensen (Big thanks to Toke). Patch #1 removes the unnecessary
rcu_barrier() when freeing bpf_cpu_map_entry and replaces it by
queue_rcu_work(). Patch #2 removes the unnecessary call_rcu() and
queue_work() when destroying cpu-map and does the freeing directly.
Test the patchset by using xdp_redirect_cpu and virtio-net. Both
xdp-mode and skb-mode have been exercised and no issues were reported.
As ususal, comments and suggestions are always welcome.
Change Log:
v1:
* address comments from Toke Høiland-Jørgensen
* add Rvb tags from Toke Høiland-Jørgensen
* update outdated comment in cpu_map_delete_elem()
RFC: https://lore.kernel.org/bpf/20230728023030.1906124-1-houtao@huaweicloud.com
====================
Link: https://lore.kernel.org/r/20230816045959.358059-1-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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After synchronous_rcu(), both the dettached XDP program and
xdp_do_flush() are completed, and the only user of bpf_cpu_map_entry
will be cpu_map_kthread_run(), so instead of calling
__cpu_map_entry_replace() to stop kthread and cleanup entry after a RCU
grace period, do these things directly.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20230816045959.358059-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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As for now __cpu_map_entry_replace() uses call_rcu() to wait for the
inflight xdp program to exit the RCU read critical section, and then
launch kworker cpu_map_kthread_stop() to call kthread_stop() to flush
all pending xdp frames or skbs.
But it is unnecessary to use rcu_barrier() in cpu_map_kthread_stop() to
wait for the completion of __cpu_map_entry_free(), because rcu_barrier()
will wait for all pending RCU callbacks and cpu_map_kthread_stop() only
needs to wait for the completion of a specific __cpu_map_entry_free().
So use queue_rcu_work() to replace call_rcu(), schedule_work() and
rcu_barrier(). queue_rcu_work() will queue a __cpu_map_entry_free()
kworker after a RCU grace period. Because __cpu_map_entry_free() is
running in a kworker context, so it is OK to do all of these freeing
procedures include kthread_stop() in it.
After the update, there is no need to do reference-counting for
bpf_cpu_map_entry, because bpf_cpu_map_entry is freed directly in
__cpu_map_entry_free(), so just remove it.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20230816045959.358059-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The qunipro_g4_sel clear is also needed for new platforms with major
version > 5. Fix the version check to take this into account.
Fixes: 9c02aa24bf40 ("scsi: ufs: ufs-qcom: Clear qunipro_g4_sel for HW version major 5")
Acked-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Nitin Rawat <quic_nitirawa@quicinc.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20230821-topic-sm8x50-upstream-ufs-major-5-plus-v2-1-f42a4b712e58@linaro.org
Reviewed-by: "Bao D. Nguyen" <quic_nguyenb@quicinc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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The search and wrap around logic in the ufshcd_mcq_sqe_search() function
does not work correctly when the hwq's queue depth is not a power of two
number. Correct it so that any queue depth with a positive integer value
within the supported range would work.
Signed-off-by: "Bao D. Nguyen" <quic_nguyenb@quicinc.com>
Link: https://lore.kernel.org/r/ff49c15be205135ed3ec186f3086694c02867dbd.1692149603.git.quic_nguyenb@quicinc.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Fixes: 8d7290348992 ("scsi: ufs: mcq: Add supporting functions for MCQ abort")
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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commit 0f8e5651095b
("of/platform: Propagate firmware node by calling device_set_node()")
use of_fwnode_handle to replace of_node_get, which introduces a side
effect that the refcount is not increased. Then the out of tree
jailhouse hypervisor enable/disable test will trigger kernel dump in
of_overlay_remove, with the following sequence
"
of_changeset_revert(&overlay_changeset);
of_changeset_destroy(&overlay_changeset);
of_overlay_remove(&overlay_id);
"
So increase the refcount to avoid issues.
This patch also release the refcount when releasing amba device to avoid
refcount leakage.
Fixes: 0f8e5651095b ("of/platform: Propagate firmware node by calling device_set_node()")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/20230821023928.3324283-2-peng.fan@oss.nxp.com
Signed-off-by: Rob Herring <robh@kernel.org>
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When a memcg is in the process of being released mem_cgroup_tryget will
fail because its reference count has already reached 0. This can happen
during reclaim if the memcg has already been offlined, and we reclaim all
remaining pages attributed to the offlined memcg. shrink_many attempts to
skip the empty memcg in this case, and continue reclaiming from the
remaining memcgs in the old generation. If there is only one memcg
remaining, or if all remaining memcgs are in the process of being released
then shrink_many will spin until all memcgs have finished being released.
The release occurs through a workqueue, so it can take a while before
kswapd is able to make any further progress.
This fix results in reductions in kswapd activity and direct reclaim in
a test where 28 apps (working set size > total memory) are repeatedly
launched in a random sequence:
A B delta ratio(%)
allocstall_movable 5962 3539 -2423 -40.64
allocstall_normal 2661 2417 -244 -9.17
kswapd_high_wmark_hit_quickly 53152 7594 -45558 -85.71
pageoutrun 57365 11750 -45615 -79.52
Link: https://lkml.kernel.org/r/20230814151636.1639123-1-tjmercier@google.com
Fixes: e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists")
Signed-off-by: T.J. Mercier <tjmercier@google.com>
Acked-by: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When page_handle_poison() fails to handle the hugepage or free page in
retry path, soft_offline_page() will return 0 while -EBUSY is expected in
this case.
Consequently the user will think soft_offline_page succeeds while it in
fact failed. So the user will not try again later in this case.
Link: https://lkml.kernel.org/r/20230627112808.1275241-1-linmiaohe@huawei.com
Fixes: b94e02822deb ("mm,hwpoison: try to narrow window race for free pages")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Recent versions of clang warn about an unused variable, though older
versions saw the 'slot++' as a use and did not warn:
radix-tree.c:1136:50: error: parameter 'slot' set but not used [-Werror,-Wunused-but-set-parameter]
It's clearly not needed any more, so just remove it.
Link: https://lkml.kernel.org/r/20230811131023.2226509-1-arnd@kernel.org
Fixes: 3a08cd52c37c7 ("radix tree: Remove multiorder support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Rong Tao <rongtao@cestc.cn>
Cc: Tom Rix <trix@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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flush_cache_vmap() must be called after new vmalloc mappings are installed
in the page table in order to allow architectures to make sure the new
mapping is visible.
It could lead to a panic since on some architectures (like powerpc),
the page table walker could see the wrong pte value and trigger a
spurious page fault that can not be resolved (see commit f1cb8f9beba8
("powerpc/64s/radix: avoid ptesync after set_pte and
ptep_set_access_flags")).
But actually the patch is aiming at riscv: the riscv specification
allows the caching of invalid entries in the TLB, and since we recently
removed the vmalloc page fault handling, we now need to emit a tlb
shootdown whenever a new vmalloc mapping is emitted
(https://lore.kernel.org/linux-riscv/20230725132246.817726-1-alexghiti@rivosinc.com/).
That's a temporary solution, there are ways to avoid that :)
Link: https://lkml.kernel.org/r/20230809164633.1556126-1-alexghiti@rivosinc.com
Fixes: 3e9a9e256b1e ("mm: add a vmap_pfn function")
Reported-by: Dylan Jhong <dylan@andestech.com>
Closes: https://lore.kernel.org/linux-riscv/ZMytNY2J8iyjbPPy@atctrx.andestech.com/
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Dylan Jhong <dylan@andestech.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
After commit 2c2241081f7d ("mm/gup: move private gup FOLL_ flags to
internal.h") FOLL_LONGTERM flag value got updated from 0x10000 to 0x100 at
include/linux/mm_types.h.
As hmm.hmm_device_private.hmm_gup_test uses FOLL_LONGTERM Updating same
here as well.
Before this change test goes in an infinite assert loop in
hmm.hmm_device_private.hmm_gup_test
==========================================================
RUN hmm.hmm_device_private.hmm_gup_test ...
hmm-tests.c:1962:hmm_gup_test:Expected HMM_DMIRROR_PROT_WRITE..
..(2) == m[2] (34)
hmm-tests.c:157:hmm_gup_test:Expected ret (-1) == 0 (0)
hmm-tests.c:157:hmm_gup_test:Expected ret (-1) == 0 (0)
...
==========================================================
Call Trace:
<TASK>
? sched_clock+0xd/0x20
? __lock_acquire.constprop.0+0x120/0x6c0
? ktime_get+0x2c/0xd0
? sched_clock+0xd/0x20
? local_clock+0x12/0xd0
? lock_release+0x26e/0x3b0
pin_user_pages_fast+0x4c/0x70
gup_test_ioctl+0x4ff/0xbb0
? gup_test_ioctl+0x68c/0xbb0
__x64_sys_ioctl+0x99/0xd0
do_syscall_64+0x60/0x90
? syscall_exit_to_user_mode+0x2a/0x50
? do_syscall_64+0x6d/0x90
? syscall_exit_to_user_mode+0x2a/0x50
? do_syscall_64+0x6d/0x90
? irqentry_exit_to_user_mode+0xd/0x20
? irqentry_exit+0x3f/0x50
? exc_page_fault+0x96/0x200
entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7f6aaa31aaff
After this change test is able to pass successfully.
Link: https://lkml.kernel.org/r/20230808124347.79163-1-ayush.jain3@amd.com
Fixes: 2c2241081f7d ("mm/gup: move private gup FOLL_ flags to internal.h")
Signed-off-by: Ayush Jain <ayush.jain3@amd.com>
Reviewed-by: Raghavendra K T <raghavendra.kt@amd.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
A syzbot stress test reported that create_empty_buffers() called from
nilfs_lookup_dirty_data_buffers() can cause a general protection fault.
Analysis using its reproducer revealed that the back reference "mapping"
from a page/folio has been changed to NULL after dirty page/folio gang
lookup in nilfs_lookup_dirty_data_buffers().
Fix this issue by excluding pages/folios from being collected if, after
acquiring a lock on each page/folio, its back reference "mapping" differs
from the pointer to the address space struct that held the page/folio.
Link: https://lkml.kernel.org/r/20230805132038.6435-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+0ad741797f4565e7e2d2@syzkaller.appspotmail.com
Closes: https://lkml.kernel.org/r/0000000000002930a705fc32b231@google.com
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
GUP-fast
In contrast to most other GUP code, GUP-fast common page table walking
code like gup_pte_range() also handles hugetlb pages. But in contrast to
other hugetlb page table walking code, it does not look at the hugetlb PTE
abstraction whereby we have only a single logical hugetlb PTE per hugetlb
page, even when using multiple cont-PTEs underneath -- which is for
example what huge_ptep_get() abstracts.
So when we have a hugetlb page that is mapped via cont-PTEs, GUP-fast
might stumble over a PTE that does not map the head page of a hugetlb page
-- not the first "head" PTE of such a cont mapping.
Logically, the whole hugetlb page is mapped (entire_mapcount == 1), but we
might end up calling gup_must_unshare() with a tail page of a hugetlb
page.
We only maintain a single PageAnonExclusive flag per hugetlb page (as
hugetlb pages cannot get partially COW-shared), stored for the head page.
That flag is clear for all tail pages.
So when gup_must_unshare() ends up calling PageAnonExclusive() with a tail
page of a hugetlb page:
1) With CONFIG_DEBUG_VM_PGFLAGS
Stumbles over the:
VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
For example, when executing the COW selftests with 64k hugetlb pages on
arm64:
[ 61.082187] page:00000000829819ff refcount:3 mapcount:1 mapping:0000000000000000 index:0x1 pfn:0x11ee11
[ 61.082842] head:0000000080f79bf7 order:4 entire_mapcount:1 nr_pages_mapped:0 pincount:2
[ 61.083384] anon flags: 0x17ffff80003000e(referenced|uptodate|dirty|head|mappedtodisk|node=0|zone=2|lastcpupid=0xfffff)
[ 61.084101] page_type: 0xffffffff()
[ 61.084332] raw: 017ffff800000000 fffffc00037b8401 0000000000000402 0000000200000000
[ 61.084840] raw: 0000000000000010 0000000000000000 00000000ffffffff 0000000000000000
[ 61.085359] head: 017ffff80003000e ffffd9e95b09b788 ffffd9e95b09b788 ffff0007ff63cf71
[ 61.085885] head: 0000000000000000 0000000000000002 00000003ffffffff 0000000000000000
[ 61.086415] page dumped because: VM_BUG_ON_PAGE(PageHuge(page) && !PageHead(page))
[ 61.086914] ------------[ cut here ]------------
[ 61.087220] kernel BUG at include/linux/page-flags.h:990!
[ 61.087591] Internal error: Oops - BUG: 00000000f2000800 [#1] SMP
[ 61.087999] Modules linked in: ...
[ 61.089404] CPU: 0 PID: 4612 Comm: cow Kdump: loaded Not tainted 6.5.0-rc4+ #3
[ 61.089917] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
[ 61.090409] pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 61.090897] pc : gup_must_unshare.part.0+0x64/0x98
[ 61.091242] lr : gup_must_unshare.part.0+0x64/0x98
[ 61.091592] sp : ffff8000825eb940
[ 61.091826] x29: ffff8000825eb940 x28: 0000000000000000 x27: fffffc00037b8440
[ 61.092329] x26: 0400000000000001 x25: 0000000000080101 x24: 0000000000080000
[ 61.092835] x23: 0000000000080100 x22: ffff0000cffb9588 x21: ffff0000c8ec6b58
[ 61.093341] x20: 0000ffffad6b1000 x19: fffffc00037b8440 x18: ffffffffffffffff
[ 61.093850] x17: 2864616548656761 x16: 5021202626202965 x15: 6761702865677548
[ 61.094358] x14: 6567615028454741 x13: 2929656761702864 x12: 6165486567615021
[ 61.094858] x11: 00000000ffff7fff x10: 00000000ffff7fff x9 : ffffd9e958b7a1c0
[ 61.095359] x8 : 00000000000bffe8 x7 : c0000000ffff7fff x6 : 00000000002bffa8
[ 61.095873] x5 : ffff0008bb19e708 x4 : 0000000000000000 x3 : 0000000000000000
[ 61.096380] x2 : 0000000000000000 x1 : ffff0000cf6636c0 x0 : 0000000000000046
[ 61.096894] Call trace:
[ 61.097080] gup_must_unshare.part.0+0x64/0x98
[ 61.097392] gup_pte_range+0x3a8/0x3f0
[ 61.097662] gup_pgd_range+0x1ec/0x280
[ 61.097942] lockless_pages_from_mm+0x64/0x1a0
[ 61.098258] internal_get_user_pages_fast+0xe4/0x1d0
[ 61.098612] pin_user_pages_fast+0x58/0x78
[ 61.098917] pin_longterm_test_start+0xf4/0x2b8
[ 61.099243] gup_test_ioctl+0x170/0x3b0
[ 61.099528] __arm64_sys_ioctl+0xa8/0xf0
[ 61.099822] invoke_syscall.constprop.0+0x7c/0xd0
[ 61.100160] el0_svc_common.constprop.0+0xe8/0x100
[ 61.100500] do_el0_svc+0x38/0xa0
[ 61.100736] el0_svc+0x3c/0x198
[ 61.100971] el0t_64_sync_handler+0x134/0x150
[ 61.101280] el0t_64_sync+0x17c/0x180
[ 61.101543] Code: aa1303e0 f00074c1 912b0021 97fffeb2 (d4210000)
2) Without CONFIG_DEBUG_VM_PGFLAGS
Always detects "not exclusive" for passed tail pages and refuses to PIN
the tail pages R/O, as gup_must_unshare() == true. GUP-fast will fallback
to ordinary GUP. As ordinary GUP properly considers the logical hugetlb
PTE abstraction in hugetlb_follow_page_mask(), pinning the page will
succeed when looking at the PageAnonExclusive on the head page only.
So the only real effect of this is that with cont-PTE hugetlb pages, we'll
always fallback from GUP-fast to ordinary GUP when not working on the head
page, which ends up checking the head page and do the right thing.
Consequently, the cow selftests pass with cont-PTE hugetlb pages as well
without CONFIG_DEBUG_VM_PGFLAGS.
Note that this only applies to anon hugetlb pages that are mapped using
cont-PTEs: for example 64k hugetlb pages on a 4k arm64 kernel.
... and only when R/O-pinning (FOLL_PIN) such pages that are mapped into
the page table R/O using GUP-fast.
On production kernels (and even most debug kernels, that don't set
CONFIG_DEBUG_VM_PGFLAGS) this patch should theoretically not be required
to be backported. But of course, it does not hurt.
Link: https://lkml.kernel.org/r/20230805101256.87306-1-david@redhat.com
Fixes: a7f226604170 ("mm/gup: trigger FAULT_FLAG_UNSHARE when R/O-pinning a possibly shared anonymous page")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Tested-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
test_kmem_basic creates 100,000 negative dentries, with each one mapping
to a slab object. After memory.high is set, these are reclaimed through
the shrink_slab function call which reclaims all 100,000 entries. The
test passes the majority of the time because when slab1 or current is
calculated, it is often above 0, however, 0 is also an acceptable value.
Link: https://lkml.kernel.org/r/7d6gcuyzdjcice6qbphrmpmv5skr5jtglg375unnjxqhstvhxc@qkn6dw6bao6v
Signed-off-by: Lucas Karpinski <lkarpins@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
walk_page_range() and friends often operate under write-locked mmap_lock.
With introduction of vma locks, the vmas have to be locked as well during
such walks to prevent concurrent page faults in these areas. Add an
additional member to mm_walk_ops to indicate locking requirements for the
walk.
The change ensures that page walks which prevent concurrent page faults
by write-locking mmap_lock, operate correctly after introduction of
per-vma locks. With per-vma locks page faults can be handled under vma
lock without taking mmap_lock at all, so write locking mmap_lock would
not stop them. The change ensures vmas are properly locked during such
walks.
A sample issue this solves is do_mbind() performing queue_pages_range()
to queue pages for migration. Without this change a concurrent page
can be faulted into the area and be left out of migration.
Link: https://lkml.kernel.org/r/20230804152724.3090321-2-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Suggested-by: Jann Horn <jannh@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michel Lespinasse <michel@lespinasse.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We shouldn't be using a GUP-internal helper if it can be avoided.
Similar to smaps_pte_entry() that uses vm_normal_page(), let's use
vm_normal_page_pmd() that similarly refuses to return the huge zeropage.
In contrast to follow_trans_huge_pmd(), vm_normal_page_pmd():
(1) Will always return the head page, not a tail page of a THP.
If we'd ever call smaps_account with a tail page while setting "compound
= true", we could be in trouble, because smaps_account() would look at
the memmap of unrelated pages.
If we're unlucky, that memmap does not exist at all. Before we removed
PG_doublemap, we could have triggered something similar as in
commit 24d7275ce279 ("fs/proc: task_mmu.c: don't read mapcount for
migration entry").
This can theoretically happen ever since commit ff9f47f6f00c ("mm: proc:
smaps_rollup: do not stall write attempts on mmap_lock"):
(a) We're in show_smaps_rollup() and processed a VMA
(b) We release the mmap lock in show_smaps_rollup() because it is
contended
(c) We merged that VMA with another VMA
(d) We collapsed a THP in that merged VMA at that position
If the end address of the original VMA falls into the middle of a THP
area, we would call smap_gather_stats() with a start address that falls
into a PMD-mapped THP. It's probably very rare to trigger when not
really forced.
(2) Will succeed on a is_pci_p2pdma_page(), like vm_normal_page()
Treat such PMDs here just like smaps_pte_entry() would treat such PTEs.
If such pages would be anonymous, we most certainly would want to
account them.
(3) Will skip over pmd_devmap(), like vm_normal_page() for pte_devmap()
As noted in vm_normal_page(), that is only for handling legacy ZONE_DEVICE
pages. So just like smaps_pte_entry(), we'll now also ignore such PMD
entries.
Especially, follow_pmd_mask() never ends up calling
follow_trans_huge_pmd() on pmd_devmap(). Instead it calls
follow_devmap_pmd() -- which will fail if neither FOLL_GET nor FOLL_PIN
is set.
So skipping pmd_devmap() pages seems to be the right thing to do.
(4) Will properly handle VM_MIXEDMAP/VM_PFNMAP, like vm_normal_page()
We won't be returning a memmap that should be ignored by core-mm, or
worse, a memmap that does not even exist. Note that while
walk_page_range() will skip VM_PFNMAP mappings, walk_page_vma() won't.
Most probably this case doesn't currently really happen on the PMD level,
otherwise we'd already be able to trigger kernel crashes when reading
smaps / smaps_rollup.
So most probably only (1) is relevant in practice as of now, but could only
cause trouble in extreme corner cases.
Let's move follow_trans_huge_pmd() to mm/internal.h to discourage future
reuse in wrong context.
Link: https://lkml.kernel.org/r/20230803143208.383663-3-david@redhat.com
Fixes: ff9f47f6f00c ("mm: proc: smaps_rollup: do not stall write attempts on mmap_lock")
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: liubo <liubo254@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Unfortunately commit 474098edac26 ("mm/gup: replace FOLL_NUMA by
gup_can_follow_protnone()") missed that follow_page() and
follow_trans_huge_pmd() never implicitly set FOLL_NUMA because they really
don't want to fail on PROT_NONE-mapped pages -- either due to NUMA hinting
or due to inaccessible (PROT_NONE) VMAs.
As spelled out in commit 0b9d705297b2 ("mm: numa: Support NUMA hinting
page faults from gup/gup_fast"): "Other follow_page callers like KSM
should not use FOLL_NUMA, or they would fail to get the pages if they use
follow_page instead of get_user_pages."
liubo reported [1] that smaps_rollup results are imprecise, because they
miss accounting of pages that are mapped PROT_NONE. Further, it's easy to
reproduce that KSM no longer works on inaccessible VMAs on x86-64, because
pte_protnone()/pmd_protnone() also indictaes "true" in inaccessible VMAs,
and follow_page() refuses to return such pages right now.
As KVM really depends on these NUMA hinting faults, removing the
pte_protnone()/pmd_protnone() handling in GUP code completely is not
really an option.
To fix the issues at hand, let's revive FOLL_NUMA as FOLL_HONOR_NUMA_FAULT
to restore the original behavior for now and add better comments.
Set FOLL_HONOR_NUMA_FAULT independent of FOLL_FORCE in
is_valid_gup_args(), to add that flag for all external GUP users.
Note that there are three GUP-internal __get_user_pages() users that don't
end up calling is_valid_gup_args() and consequently won't get
FOLL_HONOR_NUMA_FAULT set.
1) get_dump_page(): we really don't want to handle NUMA hinting
faults. It specifies FOLL_FORCE and wouldn't have honored NUMA
hinting faults already.
2) populate_vma_page_range(): we really don't want to handle NUMA hinting
faults. It specifies FOLL_FORCE on accessible VMAs, so it wouldn't have
honored NUMA hinting faults already.
3) faultin_vma_page_range(): we similarly don't want to handle NUMA
hinting faults.
To make the combination of FOLL_FORCE and FOLL_HONOR_NUMA_FAULT work in
inaccessible VMAs properly, we have to perform VMA accessibility checks in
gup_can_follow_protnone().
As GUP-fast should reject such pages either way in
pte_access_permitted()/pmd_access_permitted() -- for example on x86-64 and
arm64 that both implement pte_protnone() -- let's just always fallback to
ordinary GUP when stumbling over pte_protnone()/pmd_protnone().
As Linus notes [2], honoring NUMA faults might only make sense for
selected GUP users.
So we should really see if we can instead let relevant GUP callers specify
it manually, and not trigger NUMA hinting faults from GUP as default.
Prepare for that by making FOLL_HONOR_NUMA_FAULT an external GUP flag and
adding appropriate documenation.
While at it, remove a stale comment from follow_trans_huge_pmd(): That
comment for pmd_protnone() was added in commit 2b4847e73004 ("mm: numa:
serialise parallel get_user_page against THP migration"), which noted:
THP does not unmap pages due to a lack of support for migration
entries at a PMD level. This allows races with get_user_pages
Nowadays, we do have PMD migration entries, so the comment no longer
applies. Let's drop it.
[1] https://lore.kernel.org/r/20230726073409.631838-1-liubo254@huawei.com
[2] https://lore.kernel.org/r/CAHk-=wgRiP_9X0rRdZKT8nhemZGNateMtb366t37d8-x7VRs=g@mail.gmail.com
Link: https://lkml.kernel.org/r/20230803143208.383663-2-david@redhat.com
Fixes: 474098edac26 ("mm/gup: replace FOLL_NUMA by gup_can_follow_protnone()")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: liubo <liubo254@huawei.com>
Closes: https://lore.kernel.org/r/20230726073409.631838-1-liubo254@huawei.com
Reported-by: Peter Xu <peterx@redhat.com>
Closes: https://lore.kernel.org/all/ZMKJjDaqZ7FW0jfe@x1n/
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The intel_pstate CPU frequency scaling driver does not
use policy->cur and it is 0.
When the CPU frequency is outdated arch_freq_get_on_cpu()
will default to the nominal clock frequency when its call to
cpufreq_quick_getpolicy_cur returns the never updated 0.
Thus, the listed frequency might be outside of currently
set limits. Some users are complaining about the high
reported frequency, albeit stale, when their system is
idle and/or it is above the reduced maximum they have set.
This patch will maintain policy_cur for the intel_pstate
driver at the current minimum CPU frequency.
Reported-by: Yang Jie <yang.jie@linux.intel.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217597
Signed-off-by: Doug Smythies <dsmythies@telus.net>
[ rjw: White space damage fixes and comment adjustment ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
|
|
This reverts commit cb39c35783f26892bb1a72b1115c94fa2e77f4c5.
Patch was applied to hastily, the problem is already fixed
in Alex's vfio tree:
https://lore.kernel.org/all/20230821112237.105872b5.alex.williamson@redhat.com/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
In the worst case, the freq_table of policy data is not sorted and
contains duplicate frequencies, this means that it needs to iterate
through the entire freq_table of policy to ensure each frequency is
unique in the freq_table of stats data, this has a time complexity of
O(N^2), where N is the number of frequencies in the freq_table of
policy.
However, if the policy.freq_table is already sorted and contains no
duplicate frequencies, it can reduce the time complexity of creating
stats.freq_table to O(N), the 'freq_table_sorted' field of policy data
can be used to indicate whether the policy.freq_table is sorted.
Signed-off-by: Liao Chang <liaochang1@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
[ rjw: Fix typo in changelog, remove redundant parens ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
|
|
atomic_t variables are currently used to implement reference counters
with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows and
underflows. This is important since overflows and underflows can lead
to use-after-free situation and be exploitable.
The variable nsproxy.count is used as pure reference counter. Convert it
to refcount_t and fix up the operations.
**Important note for maintainers:
Some functions from refcount_t API defined in refcount.h have different
memory ordering guarantees than their atomic counterparts. Please check
Documentation/core-api/refcount-vs-atomic.rst for more information.
Normally the differences should not matter since refcount_t provides
enough guarantees to satisfy the refcounting use cases, but in some
rare cases it might matter. Please double check that you don't have
some undocumented memory guarantees for this variable usage.
For the nsproxy.count it might make a difference in following places:
- put_nsproxy() and switch_task_namespaces(): decrement in
refcount_dec_and_test() only provides RELEASE ordering and ACQUIRE
ordering on success vs. fully ordered atomic counterpart
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230818041327.gonna.210-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
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Other parts of the kernel may use LPS0 constraints information to make
decisions on what power state to put a device into.
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
[ rjw: Rewrite kerneldoc, rearrange if () statement, edit subject and
changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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We have one existing and one coming user of this macro.
Introduce a helper.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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While parsing the constraints show all the entries for the table
to aid with debugging other problems later.
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The constraints table should be resetting the `list` object
after running through all of `info_obj` iterations.
This adjusts whitespace as well as less code will now be included
with each loop. This fixes a functional problem is fixed where a
badly formed package in the inner loop may have incorrect data.
Fixes: 146f1ed852a8 ("ACPI: PM: s2idle: Add AMD support to handle _DSM")
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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If a badly constructed firmware includes multiple `ACPI_TYPE_PACKAGE`
objects while evaluating the AMD LPS0 _DSM, there will be a memory
leak. Explicitly guard against this.
Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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When code uses a pre-increment it makes the reader question "why".
In the constraint fetching code there is no reason for the variables
to be pre-incremented so adjust to post-increment.
No intended functional changes.
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The `#ifdef` for acpi_register_lps0_dev() currently is guarded against
`CONFIG_X86`, but actually the functions contained in the block are
specifically sleep related functions.
Adjust the guard to also check for `CONFIG_SUSPEND`.
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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There is a warning reported by kernel test robot:
smatch warnings:
drivers/net/ethernet/mellanox/mlx5/core/lib/devcom.c:264
mlx5_devcom_send_event() warn: variable dereferenced before
IS_ERR check devcom (see line 259)
The reason for the warning is that the pointer is used before check, put
the assignment to comp after devcom check to silence the warning.
Fixes: 88d162b47981 ("net/mlx5: Devcom, Infrastructure changes")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Closes: https://lore.kernel.org/r/202308041028.AkXYDwJ6-lkp@intel.com/
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
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In WQE (Work Queue Entry), the two types of data segments memories are
pointers and inline data, where inline data is passed directly as
part of the WQE.
For software steering, the maximal inline size should be less than
2*MLX5_SEND_WQE_BB, i.e., the potential data must fit with the required
inline WQE headers.
Two consecutive blocks (MLX5_SEND_WQE_BB) are not guaranteed to reside
on the same memory page. Hence, writes to MLX5_SEND_WQE_BB should be
done separately, i.e., each MLX5_SEND_WQE_BB should be obtained using
the mlx5_wq_cyc_get_wqe macro.
Signed-off-by: Itamar Gozlan <igozlan@nvidia.com>
Reviewed-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
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