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2021-09-28bpf: Replace callers of BPF_CAST_CALL with proper function typedefKees Cook
In order to keep ahead of cases in the kernel where Control Flow Integrity (CFI) may trip over function call casts, enabling -Wcast-function-type is helpful. To that end, BPF_CAST_CALL causes various warnings and is one of the last places in the kernel triggering this warning. For actual function calls, replace BPF_CAST_CALL() with a typedef, which captures the same details about the given function pointers. This change results in no object code difference. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org> Link: https://github.com/KSPP/linux/issues/20 Link: https://lore.kernel.org/lkml/CAEf4Bzb46=-J5Fxc3mMZ8JQPtK1uoE0q6+g6WPz53Cvx=CBEhw@mail.gmail.com Link: https://lore.kernel.org/bpf/20210928230946.4062144-3-keescook@chromium.org
2021-09-28bpf: Replace "want address" users of BPF_CAST_CALL with BPF_CALL_IMMKees Cook
In order to keep ahead of cases in the kernel where Control Flow Integrity (CFI) may trip over function call casts, enabling -Wcast-function-type is helpful. To that end, BPF_CAST_CALL causes various warnings and is one of the last places in the kernel triggering this warning. Most places using BPF_CAST_CALL actually just want a void * to perform math on. It's not actually performing a call, so just use a different helper to get the void *, by way of the new BPF_CALL_IMM() helper, which can clean up a common copy/paste idiom as well. This change results in no object code difference. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://github.com/KSPP/linux/issues/20 Link: https://lore.kernel.org/lkml/CAEf4Bzb46=-J5Fxc3mMZ8JQPtK1uoE0q6+g6WPz53Cvx=CBEhw@mail.gmail.com Link: https://lore.kernel.org/bpf/20210928230946.4062144-2-keescook@chromium.org
2021-09-28Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfDavid S. Miller
Daniel Borkmann says: ==================== pull-request: bpf 2021-09-28 The following pull-request contains BPF updates for your *net* tree. We've added 10 non-merge commits during the last 14 day(s) which contain a total of 11 files changed, 139 insertions(+), 53 deletions(-). The main changes are: 1) Fix MIPS JIT jump code emission for too large offsets, from Piotr Krysiuk. 2) Fix x86 JIT atomic/fetch emission when dst reg maps to rax, from Johan Almbladh. 3) Fix cgroup_sk_alloc corner case when called from interrupt, from Daniel Borkmann. 4) Fix segfault in libbpf's linker for objects without BTF, from Kumar Kartikeya Dwivedi. 5) Fix bpf_jit_charge_modmem for applications with CAP_BPF, from Lorenz Bauer. 6) Fix return value handling for struct_ops BPF programs, from Hou Tao. 7) Various fixes to BPF selftests, from Jiri Benc. ==================== Signed-off-by: David S. Miller <davem@davemloft.net> ,
2021-09-28module: fix clang CFI with MODULE_UNLOAD=nArnd Bergmann
When CONFIG_MODULE_UNLOAD is disabled, the module->exit member is not defined, causing a build failure: kernel/module.c:4493:8: error: no member named 'exit' in 'struct module' mod->exit = *exit; add an #ifdef block around this. Fixes: cf68fffb66d6 ("add support for Clang CFI") Acked-by: Kees Cook <keescook@chromium.org> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jessica Yu <jeyu@kernel.org>
2021-09-28bpf, cgroup: Assign cgroup in cgroup_sk_alloc when called from interruptDaniel Borkmann
If cgroup_sk_alloc() is called from interrupt context, then just assign the root cgroup to skcd->cgroup. Prior to commit 8520e224f547 ("bpf, cgroups: Fix cgroup v2 fallback on v1/v2 mixed mode") we would just return, and later on in sock_cgroup_ptr(), we were NULL-testing the cgroup in fast-path, and iff indeed NULL returning the root cgroup (v ?: &cgrp_dfl_root.cgrp). Rather than re-adding the NULL-test to the fast-path we can just assign it once from cgroup_sk_alloc() given v1/v2 handling has been simplified. The migration from NULL test with returning &cgrp_dfl_root.cgrp to assigning &cgrp_dfl_root.cgrp directly does /not/ change behavior for callers of sock_cgroup_ptr(). syzkaller was able to trigger a splat in the legacy netrom code base, where the RX handler in nr_rx_frame() calls nr_make_new() which calls sk_alloc() and therefore cgroup_sk_alloc() with in_interrupt() condition. Thus the NULL skcd->cgroup, where it trips over on cgroup_sk_free() side given it expects a non-NULL object. There are a few other candidates aside from netrom which have similar pattern where in their accept-like implementation, they just call to sk_alloc() and thus cgroup_sk_alloc() instead of sk_clone_lock() with the corresponding cgroup_sk_clone() which then inherits the cgroup from the parent socket. None of them are related to core protocols where BPF cgroup programs are running from. However, in future, they should follow to implement a similar inheritance mechanism. Additionally, with a !CONFIG_CGROUP_NET_PRIO and !CONFIG_CGROUP_NET_CLASSID configuration, the same issue was exposed also prior to 8520e224f547 due to commit e876ecc67db8 ("cgroup: memcg: net: do not associate sock with unrelated cgroup") which added the early in_interrupt() return back then. Fixes: 8520e224f547 ("bpf, cgroups: Fix cgroup v2 fallback on v1/v2 mixed mode") Fixes: e876ecc67db8 ("cgroup: memcg: net: do not associate sock with unrelated cgroup") Reported-by: syzbot+df709157a4ecaf192b03@syzkaller.appspotmail.com Reported-by: syzbot+533f389d4026d86a2a95@syzkaller.appspotmail.com Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: syzbot+df709157a4ecaf192b03@syzkaller.appspotmail.com Tested-by: syzbot+533f389d4026d86a2a95@syzkaller.appspotmail.com Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/bpf/20210927123921.21535-1-daniel@iogearbox.net
2021-09-28bpf: Exempt CAP_BPF from checks against bpf_jit_limitLorenz Bauer
When introducing CAP_BPF, bpf_jit_charge_modmem() was not changed to treat programs with CAP_BPF as privileged for the purpose of JIT memory allocation. This means that a program without CAP_BPF can block a program with CAP_BPF from loading a program. Fix this by checking bpf_capable() in bpf_jit_charge_modmem(). Fixes: 2c78ee898d8f ("bpf: Implement CAP_BPF") Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210922111153.19843-1-lmb@cloudflare.com
2021-09-27mm/memcg: Convert mem_cgroup_charge() to take a folioMatthew Wilcox (Oracle)
Convert all callers of mem_cgroup_charge() to call page_folio() on the page they're currently passing in. Many of them will be converted to use folios themselves soon. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: David Howells <dhowells@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz>
2021-09-26bpf: Support <8-byte scalar spill and refillMartin KaFai Lau
The verifier currently does not save the reg state when spilling <8byte bounded scalar to the stack. The bpf program will be incorrectly rejected when this scalar is refilled to the reg and then used to offset into a packet header. The later patch has a simplified bpf prog from a real use case to demonstrate this case. The current work around is to reparse the packet again such that this offset scalar is close to where the packet data will be accessed to avoid the spill. Thus, the header is parsed twice. The llvm patch [1] will align the <8bytes spill to the 8-byte stack address. This can simplify the verifier support by avoiding to store multiple reg states for each 8 byte stack slot. This patch changes the verifier to save the reg state when spilling <8bytes scalar to the stack. This reg state saving is limited to spill aligned to the 8-byte stack address. The current refill logic has already called coerce_reg_to_size(), so coerce_reg_to_size() is not called on state->stack[spi].spilled_ptr during spill. When refilling in check_stack_read_fixed_off(), it checks the refill size is the same as the number of bytes marked with STACK_SPILL before restoring the reg state. When restoring the reg state to state->regs[dst_regno], it needs to avoid the state->regs[dst_regno].subreg_def being over written because it has been marked by the check_reg_arg() earlier [check_mem_access() is called after check_reg_arg() in do_check()]. Reordering check_mem_access() and check_reg_arg() will need a lot of changes in test_verifier's tests because of the difference in verifier's error message. Thus, the patch here is to save the state->regs[dst_regno].subreg_def first in check_stack_read_fixed_off(). There are cases that the verifier needs to scrub the spilled slot from STACK_SPILL to STACK_MISC. After this patch the spill is not always in 8 bytes now, so it can no longer assume the other 7 bytes are always marked as STACK_SPILL. In particular, the scrub needs to avoid marking an uninitialized byte from STACK_INVALID to STACK_MISC. Otherwise, the verifier will incorrectly accept bpf program reading uninitialized bytes from the stack. A new helper scrub_spilled_slot() is created for this purpose. [1]: https://reviews.llvm.org/D109073 Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210922004941.625398-1-kafai@fb.com
2021-09-26bpf: Check the other end of slot_type for STACK_SPILLMartin KaFai Lau
Every 8 bytes of the stack is tracked by a bpf_stack_state. Within each bpf_stack_state, there is a 'u8 slot_type[8]' to track the type of each byte. Verifier tests slot_type[0] == STACK_SPILL to decide if the spilled reg state is saved. Verifier currently only saves the reg state if the whole 8 bytes are spilled to the stack, so checking the slot_type[7] is the same as checking slot_type[0]. The later patch will allow verifier to save the bounded scalar reg also for <8 bytes spill. There is a llvm patch [1] to ensure the <8 bytes spill will be 8-byte aligned, so checking slot_type[7] instead of slot_type[0] is required. While at it, this patch refactors the slot_type[0] == STACK_SPILL test into a new function is_spilled_reg() and change the slot_type[0] check to slot_type[7] check in there also. [1] https://reviews.llvm.org/D109073 Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210922004934.624194-1-kafai@fb.com
2021-09-26Merge tag 'timers-urgent-2021-09-26' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fix from Thomas Gleixner: "A single fix for the recently introduced regression in posix CPU timers which failed to stop the timer when requested. That caused unexpected signals to be sent to the process/thread causing malfunction" * tag 'timers-urgent-2021-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: posix-cpu-timers: Prevent spuriously armed 0-value itimer
2021-09-26Merge tag 'irq-urgent-2021-09-26' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq fixes from Thomas Gleixner: "A set of fixes for interrupt chip drivers: - Work around a bad GIC integration on a Renesas platform which can't handle byte-sized MMIO access - Plug a potential memory leak in the GICv4 driver - Fix a regression in the Armada 370-XP IPI code which was caused by issuing EOI instack of ACK. - A couple of small fixes here and there" * tag 'irq-urgent-2021-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irqchip/gic: Work around broken Renesas integration irqchip/renesas-rza1: Use semicolons instead of commas irqchip/gic-v3-its: Fix potential VPE leak on error irqchip/goldfish-pic: Select GENERIC_IRQ_CHIP to fix build irqchip/mbigen: Repair non-kernel-doc notation irqdomain: Change the type of 'size' in __irq_domain_add() to be consistent irqchip/armada-370-xp: Fix ack/eoi breakage Documentation: Fix irq-domain.rst build warning
2021-09-25Merge tag 'block-5.15-2021-09-25' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block fixes from Jens Axboe: - NVMe pull request via Christoph: - keep ctrl->namespaces ordered (Christoph Hellwig) - fix incorrect h2cdata pdu offset accounting in nvme-tcp (Sagi Grimberg) - handled updated hw_queues in nvme-fc more carefully (Daniel Wagner, James Smart) - md lock order fix (Christoph) - fallocate locking fix (Ming) - blktrace UAF fix (Zhihao) - rq-qos bio tracking fix (Ming) * tag 'block-5.15-2021-09-25' of git://git.kernel.dk/linux-block: block: hold ->invalidate_lock in blkdev_fallocate blktrace: Fix uaf in blk_trace access after removing by sysfs block: don't call rq_qos_ops->done_bio if the bio isn't tracked md: fix a lock order reversal in md_alloc nvme: keep ctrl->namespaces ordered nvme-tcp: fix incorrect h2cdata pdu offset accounting nvme-fc: remove freeze/unfreeze around update_nr_hw_queues nvme-fc: avoid race between time out and tear down nvme-fc: update hardware queues before using them
2021-09-24blktrace: Fix uaf in blk_trace access after removing by sysfsZhihao Cheng
There is an use-after-free problem triggered by following process: P1(sda) P2(sdb) echo 0 > /sys/block/sdb/trace/enable blk_trace_remove_queue synchronize_rcu blk_trace_free relay_close rcu_read_lock __blk_add_trace trace_note_tsk (Iterate running_trace_list) relay_close_buf relay_destroy_buf kfree(buf) trace_note(sdb's bt) relay_reserve buf->offset <- nullptr deference (use-after-free) !!! rcu_read_unlock [ 502.714379] BUG: kernel NULL pointer dereference, address: 0000000000000010 [ 502.715260] #PF: supervisor read access in kernel mode [ 502.715903] #PF: error_code(0x0000) - not-present page [ 502.716546] PGD 103984067 P4D 103984067 PUD 17592b067 PMD 0 [ 502.717252] Oops: 0000 [#1] SMP [ 502.720308] RIP: 0010:trace_note.isra.0+0x86/0x360 [ 502.732872] Call Trace: [ 502.733193] __blk_add_trace.cold+0x137/0x1a3 [ 502.733734] blk_add_trace_rq+0x7b/0xd0 [ 502.734207] blk_add_trace_rq_issue+0x54/0xa0 [ 502.734755] blk_mq_start_request+0xde/0x1b0 [ 502.735287] scsi_queue_rq+0x528/0x1140 ... [ 502.742704] sg_new_write.isra.0+0x16e/0x3e0 [ 502.747501] sg_ioctl+0x466/0x1100 Reproduce method: ioctl(/dev/sda, BLKTRACESETUP, blk_user_trace_setup[buf_size=127]) ioctl(/dev/sda, BLKTRACESTART) ioctl(/dev/sdb, BLKTRACESETUP, blk_user_trace_setup[buf_size=127]) ioctl(/dev/sdb, BLKTRACESTART) echo 0 > /sys/block/sdb/trace/enable & // Add delay(mdelay/msleep) before kernel enters blk_trace_free() ioctl$SG_IO(/dev/sda, SG_IO, ...) // Enters trace_note_tsk() after blk_trace_free() returned // Use mdelay in rcu region rather than msleep(which may schedule out) Remove blk_trace from running_list before calling blk_trace_free() by sysfs if blk_trace is at Blktrace_running state. Fixes: c71a896154119f ("blktrace: add ftrace plugin") Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Link: https://lore.kernel.org/r/20210923134921.109194-1-chengzhihao1@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-24Merge tag 'irqchip-fixes-5.15-1' of ↵Thomas Gleixner
git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/urgent Pull irqchip fixes from Marc Zyngier: - Work around a bad GIC integration on a Renesas platform, where the interconnect cannot deal with byte-sized MMIO accesses - Cleanup another Renesas driver abusing the comma operator - Fix a potential GICv4 memory leak on an error path - Make the type of 'size' consistent with the rest of the code in __irq_domain_add() - Fix a regression in the Armada 370-XP IPI path - Fix the build for the obviously unloved goldfish-pic - Some documentation fixes Link: https://lore.kernel.org/r/20210924090933.2766857-1-maz@kernel.org
2021-09-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
net/mptcp/protocol.c 977d293e23b4 ("mptcp: ensure tx skbs always have the MPTCP ext") efe686ffce01 ("mptcp: ensure tx skbs always have the MPTCP ext") same patch merged in both trees, keep net-next. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-09-23posix-cpu-timers: Prevent spuriously armed 0-value itimerFrederic Weisbecker
Resetting/stopping an itimer eventually leads to it being reprogrammed with an actual "0" value. As a result the itimer expires on the next tick, triggering an unexpected signal. To fix this, make sure that struct signal_struct::it[CPUCLOCK_PROF/VIRT]::expires is set to 0 when setitimer() passes a 0 it_value, indicating that the timer must stop. Fixes: 406dd42bd1ba ("posix-cpu-timers: Force next expiration recalc after itimer reset") Reported-by: Victor Stinner <vstinner@redhat.com> Reported-by: Chris Hixon <linux-kernel-bugs@hixontech.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210913145332.232023-1-frederic@kernel.org
2021-09-22entry: rseq: Call rseq_handle_notify_resume() in tracehook_notify_resume()Sean Christopherson
Invoke rseq_handle_notify_resume() from tracehook_notify_resume() now that the two function are always called back-to-back by architectures that have rseq. The rseq helper is stubbed out for architectures that don't support rseq, i.e. this is a nop across the board. Note, tracehook_notify_resume() is horribly named and arguably does not belong in tracehook.h as literally every line of code in it has nothing to do with tracing. But, that's been true since commit a42c6ded827d ("move key_repace_session_keyring() into tracehook_notify_resume()") first usurped tracehook_notify_resume() back in 2012. Punt cleaning that mess up to future patches. No functional change intended. Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210901203030.1292304-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-22KVM: rseq: Update rseq when processing NOTIFY_RESUME on xfer to KVM guestSean Christopherson
Invoke rseq's NOTIFY_RESUME handler when processing the flag prior to transferring to a KVM guest, which is roughly equivalent to an exit to userspace and processes many of the same pending actions. While the task cannot be in an rseq critical section as the KVM path is reachable only by via ioctl(KVM_RUN), the side effects that apply to rseq outside of a critical section still apply, e.g. the current CPU needs to be updated if the task is migrated. Clearing TIF_NOTIFY_RESUME without informing rseq can lead to segfaults and other badness in userspace VMMs that use rseq in combination with KVM, e.g. due to the CPU ID being stale after task migration. Fixes: 72c3c0fe54a3 ("x86/kvm: Use generic xfer to guest work function") Reported-by: Peter Foley <pefoley@google.com> Bisected-by: Doug Evans <dje@google.com> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210901203030.1292304-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-09-22irqdomain: Change the type of 'size' in __irq_domain_add() to be consistentBixuan Cui
The 'size' is used in struct_size(domain, revmap, size) and its input parameter type is 'size_t'(unsigned int). Changing the size to 'unsigned int' to make the type consistent. Signed-off-by: Bixuan Cui <cuibixuan@huawei.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210916025203.44841-1-cuibixuan@huawei.com
2021-09-20cgroup: Make rebind_subsystems() disable v2 controllers all at onceWaiman Long
It was found that the following warning was displayed when remounting controllers from cgroup v2 to v1: [ 8042.997778] WARNING: CPU: 88 PID: 80682 at kernel/cgroup/cgroup.c:3130 cgroup_apply_control_disable+0x158/0x190 : [ 8043.091109] RIP: 0010:cgroup_apply_control_disable+0x158/0x190 [ 8043.096946] Code: ff f6 45 54 01 74 39 48 8d 7d 10 48 c7 c6 e0 46 5a a4 e8 7b 67 33 00 e9 41 ff ff ff 49 8b 84 24 e8 01 00 00 0f b7 40 08 eb 95 <0f> 0b e9 5f ff ff ff 48 83 c4 08 5b 5d 41 5c 41 5d 41 5e 41 5f c3 [ 8043.115692] RSP: 0018:ffffba8a47c23d28 EFLAGS: 00010202 [ 8043.120916] RAX: 0000000000000036 RBX: ffffffffa624ce40 RCX: 000000000000181a [ 8043.128047] RDX: ffffffffa63c43e0 RSI: ffffffffa63c43e0 RDI: ffff9d7284ee1000 [ 8043.135180] RBP: ffff9d72874c5800 R08: ffffffffa624b090 R09: 0000000000000004 [ 8043.142314] R10: ffffffffa624b080 R11: 0000000000002000 R12: ffff9d7284ee1000 [ 8043.149447] R13: ffff9d7284ee1000 R14: ffffffffa624ce70 R15: ffffffffa6269e20 [ 8043.156576] FS: 00007f7747cff740(0000) GS:ffff9d7a5fc00000(0000) knlGS:0000000000000000 [ 8043.164663] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 8043.170409] CR2: 00007f7747e96680 CR3: 0000000887d60001 CR4: 00000000007706e0 [ 8043.177539] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 8043.184673] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 8043.191804] PKRU: 55555554 [ 8043.194517] Call Trace: [ 8043.196970] rebind_subsystems+0x18c/0x470 [ 8043.201070] cgroup_setup_root+0x16c/0x2f0 [ 8043.205177] cgroup1_root_to_use+0x204/0x2a0 [ 8043.209456] cgroup1_get_tree+0x3e/0x120 [ 8043.213384] vfs_get_tree+0x22/0xb0 [ 8043.216883] do_new_mount+0x176/0x2d0 [ 8043.220550] __x64_sys_mount+0x103/0x140 [ 8043.224474] do_syscall_64+0x38/0x90 [ 8043.228063] entry_SYSCALL_64_after_hwframe+0x44/0xae It was caused by the fact that rebind_subsystem() disables controllers to be rebound one by one. If more than one disabled controllers are originally from the default hierarchy, it means that cgroup_apply_control_disable() will be called multiple times for the same default hierarchy. A controller may be killed by css_kill() in the first round. In the second round, the killed controller may not be completely dead yet leading to the warning. To avoid this problem, we collect all the ssid's of controllers that needed to be disabled from the default hierarchy and then disable them in one go instead of one by one. Fixes: 334c3679ec4b ("cgroup: reimplement rebind_subsystems() using cgroup_apply_control() and friends") Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-09-20misc_cgroup: remove error log to avoid log floodChunguang Xu
In scenarios where containers are frequently created and deleted, a large number of error logs maybe generated. The logs only show which node is about to go over the max limit, not the node which resource request failed. As misc.events has provided relevant information, maybe we can remove this log. Signed-off-by: Chunguang Xu <brookxu@tencent.com> Reviewed-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-09-20misc_cgroup: introduce misc.events to count failuresChunguang Xu
Introduce misc.events to make it easier for us to understand the pressure of resources. Currently only the 'max' event is implemented, which indicates the times the resource is about to exceeds the max limit. Signed-off-by: Chunguang Xu <brookxu@tencent.com> Reviewed-by: Vipin Sharma <vipinsh@google.com> Reviewed-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-09-19audit: add filtering for io_uring recordsPaul Moore
This patch adds basic audit io_uring filtering, using as much of the existing audit filtering infrastructure as possible. In order to do this we reuse the audit filter rule's syscall mask for the io_uring operation and we create a new filter for io_uring operations as AUDIT_FILTER_URING_EXIT/audit_filter_list[7]. Thanks to Richard Guy Briggs for his review, feedback, and work on the corresponding audit userspace changes. Acked-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-09-19audit,io_uring,io-wq: add some basic audit support to io_uringPaul Moore
This patch adds basic auditing to io_uring operations, regardless of their context. This is accomplished by allocating audit_context structures for the io-wq worker and io_uring SQPOLL kernel threads as well as explicitly auditing the io_uring operations in io_issue_sqe(). Individual io_uring operations can bypass auditing through the "audit_skip" field in the struct io_op_def definition for the operation; although great care must be taken so that security relevant io_uring operations do not bypass auditing; please contact the audit mailing list (see the MAINTAINERS file) with any questions. The io_uring operations are audited using a new AUDIT_URINGOP record, an example is shown below: type=UNKNOWN[1336] msg=audit(1631800225.981:37289): uring_op=19 success=yes exit=0 items=0 ppid=15454 pid=15681 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null) Thanks to Richard Guy Briggs for review and feedback. Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-09-19audit: prepare audit_context for use in calling contexts beyond syscallsPaul Moore
This patch cleans up some of our audit_context handling by abstracting out the reset and return code fixup handling to dedicated functions. Not only does this help make things easier to read and inspect, it allows for easier reuse by future patches. We also convert the simple audit_context->in_syscall flag into an enum which can be used to by future patches to indicate a calling context other than the syscall context. Thanks to Richard Guy Briggs for review and feedback. Acked-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-09-19genirq: Disable irqfixup/poll on PREEMPT_RT.Ingo Molnar
The support for misrouted IRQs is used on old / legacy systems and is not feasible on PREEMPT_RT. Polling for interrupts reduces the overall system performance. Additionally the interrupt latency depends on the polling frequency and delays are not desired for real time workloads. Disable IRQ polling on PREEMPT_RT and let the user know that it is not enabled. The compiler will optimize the real fixup/poll code out. [ bigeasy: Update changelog and switch to IS_ENABLED() ] Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210917223841.c6j6jcaffojrnot3@linutronix.de
2021-09-19Merge tag 'perf-urgent-2021-09-19' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf event fix from Thomas Gleixner: "A single fix for the perf core where a value read with READ_ONCE() was checked and then reread which makes all the checks invalid. Reuse the already read value instead" * tag 'perf-urgent-2021-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: events: Reuse value read using READ_ONCE instead of re-reading it
2021-09-19Merge tag 'locking-urgent-2021-09-19' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fixes from Thomas Gleixner: "A set of updates for the RT specific reader/writer locking base code: - Make the fast path reader ordering guarantees correct. - Code reshuffling to make the fix simpler" [ This plays ugly games with atomic_add_return_release() because we don't have a plain atomic_add_release(), and should really be cleaned up, I think - Linus ] * tag 'locking-urgent-2021-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/rwbase: Take care of ordering guarantee for fastpath reader locking/rwbase: Extract __rwbase_write_trylock() locking/rwbase: Properly match set_and_save_state() to restore_state()
2021-09-17bpf: Add bpf_trace_vprintk helperDave Marchevsky
This helper is meant to be "bpf_trace_printk, but with proper vararg support". Follow bpf_snprintf's example and take a u64 pseudo-vararg array. Write to /sys/kernel/debug/tracing/trace_pipe using the same mechanism as bpf_trace_printk. The functionality of this helper was requested in the libbpf issue tracker [0]. [0] Closes: https://github.com/libbpf/libbpf/issues/315 Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210917182911.2426606-4-davemarchevsky@fb.com
2021-09-17bpf: Merge printk and seq_printf VARARG max macrosDave Marchevsky
MAX_SNPRINTF_VARARGS and MAX_SEQ_PRINTF_VARARGS are used by bpf helpers bpf_snprintf and bpf_seq_printf to limit their varargs. Both call into bpf_bprintf_prepare for print formatting logic and have convenience macros in libbpf (BPF_SNPRINTF, BPF_SEQ_PRINTF) which use the same helper macros to convert varargs to a byte array. Changing shared functionality to support more varargs for either bpf helper would affect the other as well, so let's combine the _VARARGS macros to make this more obvious. Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210917182911.2426606-2-davemarchevsky@fb.com
2021-09-17Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextJakub Kicinski
Alexei Starovoitov says: ==================== pull-request: bpf-next 2021-09-17 We've added 63 non-merge commits during the last 12 day(s) which contain a total of 65 files changed, 2653 insertions(+), 751 deletions(-). The main changes are: 1) Streamline internal BPF program sections handling and bpf_program__set_attach_target() in libbpf, from Andrii. 2) Add support for new btf kind BTF_KIND_TAG, from Yonghong. 3) Introduce bpf_get_branch_snapshot() to capture LBR, from Song. 4) IMUL optimization for x86-64 JIT, from Jie. 5) xsk selftest improvements, from Magnus. 6) Introduce legacy kprobe events support in libbpf, from Rafael. 7) Access hw timestamp through BPF's __sk_buff, from Vadim. * https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (63 commits) selftests/bpf: Fix a few compiler warnings libbpf: Constify all high-level program attach APIs libbpf: Schedule open_opts.attach_prog_fd deprecation since v0.7 selftests/bpf: Switch fexit_bpf2bpf selftest to set_attach_target() API libbpf: Allow skipping attach_func_name in bpf_program__set_attach_target() libbpf: Deprecated bpf_object_open_opts.relaxed_core_relocs selftests/bpf: Stop using relaxed_core_relocs which has no effect libbpf: Use pre-setup sec_def in libbpf_find_attach_btf_id() bpf: Update bpf_get_smp_processor_id() documentation libbpf: Add sphinx code documentation comments selftests/bpf: Skip btf_tag test if btf_tag attribute not supported docs/bpf: Add documentation for BTF_KIND_TAG selftests/bpf: Add a test with a bpf program with btf_tag attributes selftests/bpf: Test BTF_KIND_TAG for deduplication selftests/bpf: Add BTF_KIND_TAG unit tests selftests/bpf: Change NAME_NTH/IS_NAME_NTH for BTF_KIND_TAG format selftests/bpf: Test libbpf API function btf__add_tag() bpftool: Add support for BTF_KIND_TAG libbpf: Add support for BTF_KIND_TAG libbpf: Rename btf_{hash,equal}_int to btf_{hash,equal}_int_tag ... ==================== Link: https://lore.kernel.org/r/20210917173738.3397064-1-ast@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-09-17Merge tag 'dma-mapping-5.15-1' of git://git.infradead.org/users/hch/dma-mappingLinus Torvalds
Pull dma-mapping fixes from Christoph Hellwig: - page align size in sparc32 arch_dma_alloc (Andreas Larsson) - tone down a new dma-debug message (Hamza Mahfooz) - fix the kerneldoc for dma_map_sg_attrs (me) * tag 'dma-mapping-5.15-1' of git://git.infradead.org/users/hch/dma-mapping: sparc32: page align size in arch_dma_alloc dma-debug: prevent an error message from causing runtime problems dma-mapping: fix the kerneldoc for dma_map_sg_attrs
2021-09-17lockdep: Improve comments in wait-type checksZhouyi Zhou
Comments in wait-type checks be improved by mentioning the PREEPT_RT kernel configure option. Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Paul E. McKenney <paulmck@kernel.org> Link: https://lkml.kernel.org/r/20210811025920.20751-1-zhouzhouyi@gmail.com
2021-09-17lockdep: Let lock_is_held_type() detect recursive read as readSebastian Andrzej Siewior
lock_is_held_type(, 1) detects acquired read locks. It only recognized locks acquired with lock_acquire_shared(). Read locks acquired with lock_acquire_shared_recursive() are not recognized because a `2' is stored as the read value. Rework the check to additionally recognise lock's read value one and two as a read held lock. Fixes: e918188611f07 ("locking: More accurate annotations for read_lock()") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Boqun Feng <boqun.feng@gmail.com> Acked-by: Waiman Long <longman@redhat.com> Link: https://lkml.kernel.org/r/20210903084001.lblecrvz4esl4mrr@linutronix.de
2021-09-17kernel/locking: Add context to ww_mutex_trylock()Maarten Lankhorst
i915 will soon gain an eviction path that trylock a whole lot of locks for eviction, getting dmesg failures like below: BUG: MAX_LOCK_DEPTH too low! turning off the locking correctness validator. depth: 48 max: 48! 48 locks held by i915_selftest/5776: #0: ffff888101a79240 (&dev->mutex){....}-{3:3}, at: __driver_attach+0x88/0x160 #1: ffffc900009778c0 (reservation_ww_class_acquire){+.+.}-{0:0}, at: i915_vma_pin.constprop.63+0x39/0x1b0 [i915] #2: ffff88800cf74de8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_vma_pin.constprop.63+0x5f/0x1b0 [i915] #3: ffff88810c7f9e38 (&vm->mutex/1){+.+.}-{3:3}, at: i915_vma_pin_ww+0x1c4/0x9d0 [i915] #4: ffff88810bad5768 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915] #5: ffff88810bad60e8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915] ... #46: ffff88811964d768 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915] #47: ffff88811964e0e8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915] INFO: lockdep is turned off. Fixing eviction to nest into ww_class_acquire is a high priority, but it requires a rework of the entire driver, which can only be done one step at a time. As an intermediate solution, add an acquire context to ww_mutex_trylock, which allows us to do proper nesting annotations on the trylocks, making the above lockdep splat disappear. This is also useful in regulator_lock_nested, which may avoid dropping regulator_nesting_mutex in the uncontended path, so use it there. TTM may be another user for this, where we could lock a buffer in a fastpath with list locks held, without dropping all locks we hold. [peterz: rework actual ww_mutex_trylock() implementations] Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/YUBGPdDDjKlxAuXJ@hirez.programming.kicks-ass.net
2021-09-17genirq: Move prio assignment into the newly created threadThomas Gleixner
With enabled threaded interrupts the nouveau driver reported the following: | Chain exists of: | &mm->mmap_lock#2 --> &device->mutex --> &cpuset_rwsem | | Possible unsafe locking scenario: | | CPU0 CPU1 | ---- ---- | lock(&cpuset_rwsem); | lock(&device->mutex); | lock(&cpuset_rwsem); | lock(&mm->mmap_lock#2); The device->mutex is nvkm_device::mutex. Unblocking the lockchain at `cpuset_rwsem' is probably the easiest thing to do. Move the priority assignment to the start of the newly created thread. Fixes: 710da3c8ea7df ("sched/core: Prevent race condition between cpuset and __sched_setscheduler()") Reported-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [bigeasy: Patch description] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/a23a826af7c108ea5651e73b8fbae5e653f16e86.camel@gmx.de
2021-09-17genirq: Update irq_set_irqchip_state documentationJosh Cartwright
On RT kernels, the use of migrate_disable()/migrate_enable() is sufficient to guarantee a task isn't moved to another CPU. Update the irq_set_irqchip_state() documentation to reflect this. Signed-off-by: Josh Cartwright <joshc@ni.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210917103055.92150-1-bigeasy@linutronix.de
2021-09-16Merge tag 'net-5.15-rc2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net Pull networking fixes from Jakub Kicinski: "Including fixes from bpf. Current release - regressions: - vhost_net: fix OoB on sendmsg() failure - mlx5: bridge, fix uninitialized variable usage - bnxt_en: fix error recovery regression Current release - new code bugs: - bpf, mm: fix lockdep warning triggered by stack_map_get_build_id_offset() Previous releases - regressions: - r6040: restore MDIO clock frequency after MAC reset - tcp: fix tp->undo_retrans accounting in tcp_sacktag_one() - dsa: flush switchdev workqueue before tearing down CPU/DSA ports Previous releases - always broken: - ptp: dp83640: don't define PAGE0, avoid compiler warning - igc: fix tunnel segmentation offloads - phylink: update SFP selected interface on advertising changes - stmmac: fix system hang caused by eee_ctrl_timer during suspend/resume - mlx5e: fix mutual exclusion between CQE compression and HW TS Misc: - bpf, cgroups: fix cgroup v2 fallback on v1/v2 mixed mode - sfc: fallback for lack of xdp tx queues - hns3: add option to turn off page pool feature" * tag 'net-5.15-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (67 commits) mlxbf_gige: clear valid_polarity upon open igc: fix tunnel offloading net/{mlx5|nfp|bnxt}: Remove unnecessary RTNL lock assert net: wan: wanxl: define CROSS_COMPILE_M68K selftests: nci: replace unsigned int with int net: dsa: flush switchdev workqueue before tearing down CPU/DSA ports Revert "net: phy: Uniform PHY driver access" net: dsa: destroy the phylink instance on any error in dsa_slave_phy_setup ptp: dp83640: don't define PAGE0 bnx2x: Fix enabling network interfaces without VFs Revert "Revert "ipv4: fix memory leaks in ip_cmsg_send() callers"" tcp: fix tp->undo_retrans accounting in tcp_sacktag_one() net-caif: avoid user-triggerable WARN_ON(1) bpf, selftests: Add test case for mixed cgroup v1/v2 bpf, selftests: Add cgroup v1 net_cls classid helpers bpf, cgroups: Fix cgroup v2 fallback on v1/v2 mixed mode bpf: Add oversize check before call kvcalloc() net: hns3: fix the timing issue of VF clearing interrupt sources net: hns3: fix the exception when query imp info net: hns3: disable mac in flr process ...
2021-09-16scftorture: Warn on individual scf_torture_init() error conditionsPaul E. McKenney
When running scftorture as a module, any scf_torture_init() issues will be reflected in the error code from modprobe or insmod, as the case may be. However, these error codes are not available when running scftorture built-in, for example, when using the kvm.sh script. This commit therefore adds WARN_ON_ONCE() to allow distinguishing scf_torture_init() errors when running scftorture built-in. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-09-16scftorture: Count reschedule IPIsPaul E. McKenney
Currently, only those IPIs that invoke scftorture's scf_handler() IPI handler function are counted. This means that runs exercising only scftorture.weight_resched will look like they have made no forward progress, resulting in "GP HANG" complaints from the rcutorture scripting. This commit therefore increments the scf_invoked_count per-CPU counter immediately after calling resched_cpu(). Fixes: 1ac78b49d61d4 ("scftorture: Add an alternative IPI vector") Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-09-16scftorture: Account for weight_resched when checking for all zeroesPaul E. McKenney
The "all zero weights makes no sense" error is emitted even when scftorture.weight_resched is non-zero because it was left out of the enclosing "if" condition. This commit adds it in. Fixes: 1ac78b49d61d4 ("scftorture: Add an alternative IPI vector") Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-09-16scftorture: Shut down if nonsensical arguments givenPaul E. McKenney
If (say) a 10-hour scftorture run is started, but the module parameters are so nonsensical that the run doesn't even start, then scftorture will wait the full ten hours when run built into a guest OS. This commit therefore shuts down the system in this case so that the error is reported immediately instead of ten hours hence. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-09-16scftorture: Allow zero weight to exclude an smp_call_function*() categoryPaul E. McKenney
This commit reworks the weighting calculations to allow zero to be specified to disable a given weight. For example, specifying the scftorture.weight_resched=0 kernel boot parameter without specifying a non-zero value for any of the other scftorture.weight_* parameters would provide the default weights for the others, but would refrain from doing any resched-based IPIs. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-09-16rcu: Avoid unneeded function call in rcu_read_unlock()Waiman Long
Since commit aa40c138cc8f3 ("rcu: Report QS for outermost PREEMPT=n rcu_read_unlock() for strict GPs") the function rcu_read_unlock_strict() is invoked by the inlined rcu_read_unlock() function. However, rcu_read_unlock_strict() is an empty function in production kernels, which are built with CONFIG_RCU_STRICT_GRACE_PERIOD=n. There is a mention of rcu_read_unlock_strict() in the BPF verifier, but this is in a deny-list, meaning that BPF does not care whether rcu_read_unlock_strict() is ever called. This commit therefore provides a slight performance improvement by hoisting the check of CONFIG_RCU_STRICT_GRACE_PERIOD from rcu_read_unlock_strict() into rcu_read_unlock(), thus avoiding the pointless call to an empty function. Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-09-15rcu-tasks: Update comments to cond_resched_tasks_rcu_qs()Paul E. McKenney
The cond_resched_rcu_qs() function no longer exists, despite being mentioned several times in kernel/rcu/tasks.h. This commit therefore updates it to the current cond_resched_tasks_rcu_qs(). Reported-by: Neeraj Upadhyay <neeraju@codeaurora.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-09-15rcu-tasks: Fix IPI failure handling in trc_wait_for_one_readerNeeraj Upadhyay
The trc_wait_for_one_reader() function is called at multiple stages of trace rcu-tasks GP function, rcu_tasks_wait_gp(): - First, it is called as part of per task function - rcu_tasks_trace_pertask(), for all non-idle tasks. As part of per task processing, this function add the task in the holdout list and if the task is currently running on a CPU, it sends IPI to the task's CPU. The IPI handler takes action depending on whether task is in trace rcu-tasks read side critical section or not: - a. If the task is in trace rcu-tasks read side critical section (t->trc_reader_nesting != 0), the IPI handler sets the task's ->trc_reader_special.b.need_qs, so that this task notifies exit from its outermost read side critical section (by decrementing trc_n_readers_need_end) to the GP handling function. trc_wait_for_one_reader() also increments trc_n_readers_need_end, so that the trace rcu-tasks GP handler function waits for this task's read side exit notification. The IPI handler also sets t->trc_reader_checked to true, and no further IPIs are sent for this task, for this trace rcu-tasks grace period and this task can be removed from holdout list. - b. If the task is in the process of exiting its trace rcu-tasks read side critical section, (t->trc_reader_nesting < 0), defer this task's processing to future calls to trc_wait_for_one_reader(). - c. If task is not in rcu-task read side critical section, t->trc_reader_nesting == 0, ->trc_reader_checked is set for this task, so that this task is removed from holdout list. - Second, trc_wait_for_one_reader() is called as part of post scan, in function rcu_tasks_trace_postscan(), for all idle tasks. - Third, in function check_all_holdout_tasks_trace(), this function is called for each task in the holdout list, but only if there isn't a pending IPI for the task (->trc_ipi_to_cpu == -1). This function removed the task from holdout list, if IPI handler has completed the required work, to ensure that the current trace rcu-tasks grace period either waits for this task, or this task is not in a trace rcu-tasks read side critical section. Now, considering the scenario where smp_call_function_single() fails in first case, inside rcu_tasks_trace_pertask(). In this case, ->trc_ipi_to_cpu is set to the current CPU for that task. This will result in trc_wait_for_one_reader() getting skipped in third case, inside check_all_holdout_tasks_trace(), for this task. This further results in ->trc_reader_checked never getting set for this task, and the task not getting removed from holdout list. This can cause the current trace rcu-tasks grace period to stall. Fix the above problem, by resetting ->trc_ipi_to_cpu to -1, on smp_call_function_single() failure, so that future IPI calls can be send for this task. Note that all three of the trc_wait_for_one_reader() function's callers (rcu_tasks_trace_pertask(), rcu_tasks_trace_postscan(), check_all_holdout_tasks_trace()) hold cpu_read_lock(). This means that smp_call_function_single() cannot race with CPU hotplug, and thus should never fail. Therefore, also add a warning in order to report any such failure in case smp_call_function_single() grows some other reason for failure. Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-09-15rcu-tasks: Fix read-side primitives comment for call_rcu_tasks_traceNeeraj Upadhyay
call_rcu_tasks_trace() does have read-side primitives - rcu_read_lock_trace() and rcu_read_unlock_trace(). Fix this information in the comments. Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-09-15rcu-tasks: Clarify read side section info for rcu_tasks_rude GP primitivesNeeraj Upadhyay
RCU tasks rude variant does not check whether the current running context on a CPU is usermode. Read side critical section ends on transition to usermode execution, by the virtue of usermode execution being schedulable. Clarify this in comments for call_rcu_tasks_rude() and synchronize_rcu_tasks_rude(). Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-09-15rcu-tasks: Correct comparisons for CPU numbers in show_stalled_task_traceNeeraj Upadhyay
Valid CPU numbers can be zero or greater, but the checks for ->trc_ipi_to_cpu and tick_nohz_full_cpu()'s argument are for strictly greater than. This commit therefore corrects the check for no_hz_full cpu in show_stalled_task_trace() so as to include cpu 0. Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-09-15rcu-tasks: Correct firstreport usage in check_all_holdout_tasks_traceNeeraj Upadhyay
In check_all_holdout_tasks_trace(), firstreport is a pointer argument; so, check the dereferenced value, instead of checking the pointer. Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
generated by cgit (git 2.34.1) at 2025-09-12 11:58:59 +0000