From: kernel test robot <oliver.sang@intel.com>
To: Christoph Hellwig <hch@lst.de>
Cc: <oe-lkp@lists.linux.dev>, <lkp@intel.com>,
Christoph Hellwig <hch@lst.de>, <oliver.sang@intel.com>
Subject: [hch-misc:nfs-delegation-lru] [NFS] 7f634b9540: WARNING:suspicious_RCU_usage
Date: Fri, 21 Nov 2025 14:24:22 +0800 [thread overview]
Message-ID: <202511211332.c5d11bb6-lkp@intel.com> (raw)
Hello,
kernel test robot noticed "WARNING:suspicious_RCU_usage" on:
commit: 7f634b9540f882dc4ec7a131c4e2571005457b3d ("NFS: take a delegation reference in nfs4_get_valid_delegation")
git://git.infradead.org/users/hch/misc.git nfs-delegation-lru
in testcase: perf-sanity-tests
version:
with following parameters:
perf_compiler: clang
group: group-01
config: x86_64-rhel-9.4-bpf
compiler: gcc-14
test machine: 16 threads 1 sockets Intel(R) Xeon(R) E-2278G CPU @ 3.40GHz (Coffee Lake-E) with 32G memory
(please refer to attached dmesg/kmsg for entire log/backtrace)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202511211332.c5d11bb6-lkp@intel.com
[ 157.851875][T11003] WARNING: suspicious RCU usage
[ 157.857927][T11003] 6.18.0-rc5-00346-g7f634b9540f8 #1 Tainted: G S
[ 157.867085][T11003] -----------------------------
[ 157.872699][T11003] fs/nfs/delegation.c:103 suspicious rcu_dereference_check() usage!
[ 157.881467][T11003]
[ 157.881467][T11003] other info that might help us debug this:
[ 157.881467][T11003]
[ 157.894190][T11003]
[ 157.894190][T11003] rcu_scheduler_active = 2, debug_locks = 1
[ 157.903901][T11003] no locks held by xz/11003.
[ 157.909285][T11003]
[ 157.909285][T11003] stack backtrace:
[ 157.916841][T11003] CPU: 2 UID: 0 PID: 11003 Comm: xz Tainted: G S 6.18.0-rc5-00346-g7f634b9540f8 #1 PREEMPT(full)
[ 157.916846][T11003] Tainted: [S]=CPU_OUT_OF_SPEC
[ 157.916848][T11003] Hardware name: Intel Corporation Mehlow UP Server Platform/Moss Beach Server, BIOS CNLSE2R1.R00.X188.B13.1903250419 03/25/2019
[ 157.916850][T11003] Call Trace:
[ 157.916852][T11003] <TASK>
[ 157.916855][T11003] dump_stack_lvl (lib/dump_stack.c:122)
[ 157.916862][T11003] lockdep_rcu_suspicious.cold (kernel/locking/lockdep.c:6877)
[ 157.916868][T11003] nfs4_get_valid_delegation (fs/nfs/delegation.c:103 (discriminator 9)) nfsv4
[ 157.917012][T11003] ? __pfx_nfs4_get_valid_delegation (fs/nfs/delegation.c:100) nfsv4
[ 157.917153][T11003] _nfs4_do_open+0x155/0x720 nfsv4
[ 157.917329][T11003] ? __pfx__nfs4_do_open+0x10/0x10 nfsv4
[ 157.917461][T11003] ? kasan_save_stack (mm/kasan/common.c:58)
[ 157.917464][T11003] ? kasan_save_stack (mm/kasan/common.c:57)
[ 157.917466][T11003] ? kasan_save_track (mm/kasan/common.c:69 (discriminator 1) mm/kasan/common.c:78 (discriminator 1))
[ 157.917469][T11003] ? __kasan_kmalloc (mm/kasan/common.c:400 mm/kasan/common.c:417)
[ 157.917473][T11003] ? alloc_nfs_open_context (fs/nfs/inode.c:1212)
[ 157.917480][T11003] nfs4_do_open (fs/nfs/nfs4proc.c:3343) nfsv4
[ 157.917611][T11003] ? __pfx_nfs4_do_open (fs/nfs/nfs4proc.c:3325) nfsv4
[ 157.917744][T11003] ? find_held_lock (kernel/locking/lockdep.c:5350 (discriminator 1))
[ 157.917748][T11003] ? __memcg_slab_post_alloc_hook (include/linux/rcupdate.h:341 include/linux/rcupdate.h:897 include/linux/percpu-refcount.h:209 include/linux/percpu-refcount.h:222 include/linux/memcontrol.h:780 mm/memcontrol.c:3193)
[ 157.917755][T11003] ? __lock_acquire (kernel/locking/lockdep.c:5237 (discriminator 1))
[ 157.917759][T11003] ? lock_release (kernel/locking/lockdep.c:470 (discriminator 4) kernel/locking/lockdep.c:5891 (discriminator 4) kernel/locking/lockdep.c:5875 (discriminator 4))
[ 157.917762][T11003] ? __rcu_read_unlock (kernel/rcu/tree_plugin.h:441 (discriminator 1))
[ 157.917769][T11003] nfs4_atomic_open (fs/nfs/nfs4proc.c:3919) nfsv4
[ 157.917899][T11003] ? __pfx_nfs4_atomic_open (fs/nfs/nfs4proc.c:3912) nfsv4
[ 157.918029][T11003] ? alloc_nfs_open_context (fs/nfs/inode.c:1215 (discriminator 1))
[ 157.918033][T11003] ? __lock_release+0x5d/0x180
[ 157.918037][T11003] ? rcu_is_watching (arch/x86/include/asm/atomic.h:23 include/linux/atomic/atomic-arch-fallback.h:457 include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[ 157.918041][T11003] ? trace_preempt_on (include/trace/events/preemptirq.h:53 (discriminator 2) kernel/trace/trace_preemptirq.c:120 (discriminator 2))
[ 157.918046][T11003] ? preempt_count_sub (kernel/sched/core.c:5813 kernel/sched/core.c:5809 kernel/sched/core.c:5831)
[ 157.918054][T11003] nfs4_file_open (fs/nfs/nfs4file.c:73 (discriminator 1)) nfsv4
[ 157.918193][T11003] ? __pfx_nfs4_file_open (fs/nfs/nfs4file.c:30) nfsv4
[ 157.918368][T11003] ? rcu_is_watching (arch/x86/include/asm/atomic.h:23 include/linux/atomic/atomic-arch-fallback.h:457 include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[ 157.918374][T11003] ? lock_release (kernel/locking/lockdep.c:470 (discriminator 4) kernel/locking/lockdep.c:5891 (discriminator 4) kernel/locking/lockdep.c:5875 (discriminator 4))
[ 157.918378][T11003] ? __bpf_tramp_exit (kernel/bpf/trampoline.c:1052)
[ 157.918382][T11003] ? __rcu_read_unlock (kernel/rcu/tree_plugin.h:441 (discriminator 1))
[ 157.918387][T11003] ? bpf_trampoline_6442519885+0x9f/0xf1
[ 157.918390][T11003] ? fsnotify_open_perm_and_set_mode (include/linux/fsnotify_backend.h:579 (discriminator 2) include/linux/fsnotify.h:24 (discriminator 2) fs/notify/fsnotify.c:679 (discriminator 2))
[ 157.918397][T11003] do_dentry_open (fs/open.c:965)
[ 157.918402][T11003] ? __pfx_nfs4_file_open (fs/nfs/nfs4file.c:30) nfsv4
[ 157.918540][T11003] vfs_open (fs/open.c:1097)
[ 157.918543][T11003] ? security_inode_permission (security/security.c:2363 (discriminator 1))
[ 157.918550][T11003] do_open (fs/nfs/dir.c:2664)
[ 157.918556][T11003] path_openat (fs/namei.c:4135)
[ 157.918560][T11003] ? __lock_acquire (kernel/locking/lockdep.c:5237 (discriminator 1))
[ 157.918564][T11003] ? __pfx_path_openat (fs/namei.c:4116)
[ 157.918573][T11003] do_filp_open (fs/namei.c:4162 (discriminator 2))
[ 157.918578][T11003] ? __pfx_do_filp_open (fs/namei.c:4155)
[ 157.918581][T11003] ? lock_acquire (include/linux/preempt.h:471 (discriminator 2) include/trace/events/lock.h:24 (discriminator 2) include/trace/events/lock.h:24 (discriminator 2) kernel/locking/lockdep.c:5831 (discriminator 2))
[ 157.918591][T11003] ? find_held_lock (kernel/locking/lockdep.c:5350 (discriminator 1))
[ 157.918594][T11003] ? alloc_fd (fs/file.c:613)
[ 157.918599][T11003] ? alloc_fd (fs/file.c:613)
[ 157.918605][T11003] ? preempt_count_sub (kernel/sched/core.c:5813 kernel/sched/core.c:5809 kernel/sched/core.c:5831)
[ 157.918609][T11003] ? _raw_spin_unlock (include/linux/spinlock_api_smp.h:143 (discriminator 3) kernel/locking/spinlock.c:186 (discriminator 3))
[ 157.918613][T11003] ? alloc_fd (fs/file.c:613)
[ 157.918620][T11003] do_sys_openat2 (fs/open.c:1437)
[ 157.918624][T11003] ? __pfx_do_sys_openat2 (fs/open.c:1422)
[ 157.918629][T11003] ? preempt_count_sub (kernel/sched/core.c:5813 kernel/sched/core.c:5809 kernel/sched/core.c:5831)
[ 157.918633][T11003] ? _raw_spin_unlock_irq (include/linux/spinlock_api_smp.h:160 (discriminator 3) kernel/locking/spinlock.c:202 (discriminator 3))
[ 157.918639][T11003] __x64_sys_openat (fs/open.c:1463)
[ 157.918643][T11003] ? __pfx___x64_sys_openat (fs/open.c:1463)
[ 157.918648][T11003] ? lock_release (kernel/locking/lockdep.c:470 (discriminator 4) kernel/locking/lockdep.c:5891 (discriminator 4) kernel/locking/lockdep.c:5875 (discriminator 4))
[ 157.918653][T11003] ? do_syscall_64 (arch/x86/include/asm/irqflags.h:42 arch/x86/include/asm/irqflags.h:119 include/linux/entry-common.h:124 arch/x86/entry/syscall_64.c:90)
[ 157.918659][T11003] do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
[ 157.918665][T11003] ? __lock_acquire (kernel/locking/lockdep.c:5237 (discriminator 1))
[ 157.918670][T11003] ? lock_acquire (include/linux/preempt.h:471 (discriminator 2) include/trace/events/lock.h:24 (discriminator 2) include/trace/events/lock.h:24 (discriminator 2) kernel/locking/lockdep.c:5831 (discriminator 2))
[ 157.918676][T11003] ? find_held_lock (kernel/locking/lockdep.c:5350 (discriminator 1))
[ 157.918679][T11003] ? __x64_sys_rt_sigprocmask (kernel/signal.c:3340 kernel/signal.c:3318 kernel/signal.c:3318)
[ 157.918683][T11003] ? __x64_sys_rt_sigprocmask (kernel/signal.c:3340 kernel/signal.c:3318 kernel/signal.c:3318)
[ 157.918685][T11003] ? __lock_release+0x5d/0x180
[ 157.918689][T11003] ? rcu_is_watching (arch/x86/include/asm/atomic.h:23 include/linux/atomic/atomic-arch-fallback.h:457 include/linux/context_tracking.h:128 kernel/rcu/tree.c:751)
[ 157.918693][T11003] ? trace_preempt_on (include/trace/events/preemptirq.h:53 (discriminator 2) kernel/trace/trace_preemptirq.c:120 (discriminator 2))
[ 157.918697][T11003] ? preempt_count_sub (kernel/sched/core.c:5813 kernel/sched/core.c:5809 kernel/sched/core.c:5831)
[ 157.918702][T11003] ? _raw_spin_unlock_irq (include/linux/spinlock_api_smp.h:160 (discriminator 3) kernel/locking/spinlock.c:202 (discriminator 3))
[ 157.918705][T11003] ? __x64_sys_rt_sigprocmask (kernel/signal.c:3340 kernel/signal.c:3318 kernel/signal.c:3318)
[ 157.918708][T11003] ? __pfx___x64_sys_rt_sigprocmask (kernel/signal.c:3318)
[ 157.918715][T11003] ? __pfx___x64_sys_rt_sigaction (kernel/signal.c:4629)
[ 157.918718][T11003] ? __x64_sys_sched_getaffinity (kernel/sched/syscalls.c:1318)
[ 157.918722][T11003] ? do_syscall_64 (include/linux/irq-entry-common.h:257 include/linux/entry-common.h:212 arch/x86/entry/syscall_64.c:100)
[ 157.918728][T11003] ? do_syscall_64 (arch/x86/entry/syscall_64.c:113)
[ 157.918732][T11003] ? do_syscall_64 (include/linux/irq-entry-common.h:257 include/linux/entry-common.h:212 arch/x86/entry/syscall_64.c:100)
[ 157.918736][T11003] ? do_syscall_64 (include/linux/irq-entry-common.h:257 include/linux/entry-common.h:212 arch/x86/entry/syscall_64.c:100)
[ 157.918741][T11003] ? do_syscall_64 (arch/x86/entry/syscall_64.c:113)
[ 157.918745][T11003] ? clear_bhb_loop (arch/x86/entry/entry_64.S:1548)
[ 157.918750][T11003] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[ 157.918753][T11003] RIP: 0033:0x7f07ff473687
[ 157.918770][T11003] Code: 48 89 fa 4c 89 df e8 58 b3 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
All code
========
0: 48 89 fa mov %rdi,%rdx
3: 4c 89 df mov %r11,%rdi
6: e8 58 b3 00 00 call 0xb363
b: 8b 93 08 03 00 00 mov 0x308(%rbx),%edx
11: 59 pop %rcx
12: 5e pop %rsi
13: 48 83 f8 fc cmp $0xfffffffffffffffc,%rax
17: 74 1a je 0x33
19: 5b pop %rbx
1a: c3 ret
1b: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1)
22: 00
23: 48 8b 44 24 10 mov 0x10(%rsp),%rax
28: 0f 05 syscall
2a:* 5b pop %rbx <-- trapping instruction
2b: c3 ret
2c: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)
33: 83 e2 39 and $0x39,%edx
36: 83 fa 08 cmp $0x8,%edx
39: 75 de jne 0x19
3b: e8 23 ff ff ff call 0xffffffffffffff63
Code starting with the faulting instruction
===========================================
0: 5b pop %rbx
1: c3 ret
2: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)
9: 83 e2 39 and $0x39,%edx
c: 83 fa 08 cmp $0x8,%edx
f: 75 de jne 0xffffffffffffffef
11: e8 23 ff ff ff call 0xffffffffffffff39
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20251121/202511211332.c5d11bb6-lkp@intel.com
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
reply other threads:[~2025-11-21 6:24 UTC|newest]
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