From: kernel test robot <oliver.sang@intel.com>
To: David Sterba <dsterba@suse.com>
Cc: <oe-lkp@lists.linux.dev>, <lkp@intel.com>,
<linux-btrfs@vger.kernel.org>, David Sterba <dsterba@suse.com>,
<oliver.sang@intel.com>
Subject: Re: [PATCH] btrfs: sink RCU protection to _btrfs_printk()
Date: Fri, 13 Feb 2026 10:08:08 +0800 [thread overview]
Message-ID: <202602130950.db059ac8-lkp@intel.com> (raw)
In-Reply-To: <20260205114546.210418-1-dsterba@suse.com>
Hello,
kernel test robot noticed "WARNING:suspicious_RCU_usage" on:
commit: a7bc95298723a9c79cc429adfb7dc1f37ff55a8d ("[PATCH] btrfs: sink RCU protection to _btrfs_printk()")
url: https://github.com/intel-lab-lkp/linux/commits/David-Sterba/btrfs-sink-RCU-protection-to-_btrfs_printk/20260205-194735
base: https://git.kernel.org/cgit/linux/kernel/git/kdave/linux.git for-next
patch link: https://lore.kernel.org/all/20260205114546.210418-1-dsterba@suse.com/
patch subject: [PATCH] btrfs: sink RCU protection to _btrfs_printk()
in testcase: perf-sanity-tests
version:
with following parameters:
perf_compiler: clang
group: group-02
config: x86_64-rhel-9.4-bpf
compiler: gcc-14
test machine: 64 threads 2 sockets Intel(R) Xeon(R) Gold 6346 CPU @ 3.10GHz (Ice Lake) with 256G 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/202602130950.db059ac8-lkp@intel.com
kern :warn : [ 282.723760] [ T5053] WARNING: suspicious RCU usage
kern :warn : [ 282.723764] [ T5053] 6.19.0-rc8-00144-ga7bc95298723 #1 Tainted: G S
kern :warn : [ 282.723768] [ T5053] -----------------------------
kern :warn : [ 282.723769] [ T5053] fs/btrfs/volumes.h:856 suspicious rcu_dereference_check() usage!
kern :warn : [ 282.723773] [ T5053]
other info that might help us debug this:
kern :warn : [ 282.723775] [ T5053]
rcu_scheduler_active = 2, debug_locks = 1
kern :warn : [ 282.723778] [ T5053] 4 locks held by mount/5053:
kern :warn : [ 282.723780] [ T5053] #0: ff1100058fa07c70 (&fc->uapi_mutex){+.+.}-{4:4}, at: __do_sys_fsconfig (fs/fsopen.c:472)
kern :warn : [ 282.733684] [ T5053] #1: ff1100080763a0e0 (&type->s_umount_key#45
user :notice: [ 282.739077] [ T979] File "/usr/bin/py3clean", line 209, in <module>
kern :warn : [ 282.746062] [ T5053] /1
kern :warn : [ 282.758521] [ T5053] ){+.+.}-{4:4}, at: alloc_super (fs/super.c:346)
user :notice: [ 282.768758] [ T979] main()
kern :warn : [ 282.776531] [ T5053] #2: ff110005cb3fb8d8 (&fs_devs->device_list_mutex){+.+.}-{4:4}
kern :warn : [ 282.790726] [ T5053] , at: btrfs_init_dev_stats (fs/btrfs/volumes.c:7975) btrfs
user :notice: [ 282.793082] [ T979] ~~~~^^
kern :warn : [ 282.799023] [ T5053] #3:
kern :warn : [ 282.807834] [ T5053] ff1100019d555d18 (btrfs-dev-00
user :notice: [ 282.810637] [ T979] File "/usr/bin/py3clean", line 195, in main
kern :warn : [ 282.815878] [ T5053] ){.+.+}-{4:4}, at: btrfs_tree_read_lock_nested (arch/x86/include/asm/jump_label.h:37 include/trace/events/btrfs.h:2293 fs/btrfs/locking.c:147) btrfs
kern :warn : [ 282.826610] [ T5053]
stack backtrace:
kern :warn : [ 282.826616] [ T5053] CPU: 9 UID: 0 PID: 5053 Comm: mount Tainted: G S 6.19.0-rc8-00144-ga7bc95298723 #1 PREEMPT(full)
kern :warn : [ 282.826622] [ T5053] Tainted: [S]=CPU_OUT_OF_SPEC
kern :warn : [ 282.826624] [ T5053] Hardware name: Inspur NF5180M6/NF5180M6, BIOS 06.00.04 04/12/2022
kern :warn : [ 282.826626] [ T5053] Call Trace:
kern :warn : [ 282.826630] [ T5053] <TASK>
kern :warn : [ 282.826632] [ T5053] dump_stack_lvl (lib/dump_stack.c:122)
kern :warn : [ 282.826640] [ T5053] lockdep_rcu_suspicious.cold (kernel/locking/lockdep.c:6877)
kern :warn : [ 282.826648] [ T5053] btrfs_dev_name (fs/btrfs/volumes.h:856 (discriminator 9) fs/btrfs/volumes.h:851 (discriminator 9)) btrfs
kern :warn : [ 282.826845] [ T5053] btrfs_device_init_dev_stats (fs/btrfs/volumes.c:8119 (discriminator 6) fs/btrfs/volumes.c:7957 (discriminator 6)) btrfs
kern :warn : [ 282.827048] [ T5053] ? __pfx_btrfs_device_init_dev_stats (fs/btrfs/volumes.c:7921) btrfs
kern :warn : [ 282.827256] [ T5053] ? kasan_save_track (mm/kasan/common.c:70 (discriminator 1) mm/kasan/common.c:79 (discriminator 1))
kern :warn : [ 282.827262] [ T5053] ? __kasan_slab_alloc (mm/kasan/common.c:340 mm/kasan/common.c:366)
kern :warn : [ 282.827267] [ T5053] ? __rcu_read_lock (kernel/rcu/tree_plugin.h:416 (discriminator 2))
kern :warn : [ 282.827273] [ T5053] ? kmem_cache_alloc_noprof (include/trace/events/kmem.h:12 (discriminator 2) mm/slub.c:5273 (discriminator 2))
kern :warn : [ 282.827280] [ T5053] ? btrfs_init_dev_stats (fs/btrfs/volumes.c:7970) btrfs
kern :warn : [ 282.827494] [ T5053] btrfs_init_dev_stats (fs/btrfs/volumes.c:7977) btrfs
kern :warn : [ 282.827707] [ T5053] open_ctree (fs/btrfs/disk-io.c:3546) btrfs
kern :warn : [ 282.827910] [ T5053] btrfs_get_tree_super.cold (fs/btrfs/super.c:982 fs/btrfs/super.c:1944) btrfs
kern :warn : [ 282.828112] [ T5053] btrfs_get_tree_subvol (fs/btrfs/super.c:2087) btrfs
kern :warn : [ 282.828315] [ T5053] vfs_get_tree (fs/super.c:1751)
kern :warn : [ 282.828322] [ T5053] vfs_cmd_create (fs/fsopen.c:231)
kern :warn : [ 282.828328] [ T5053] __do_sys_fsconfig (fs/fsopen.c:474)
kern :warn : [ 282.828333] [ T5053] ? __pfx___do_sys_fsconfig (fs/fsopen.c:356)
kern :warn : [ 282.828337] [ T5053] ? do_faccessat (fs/open.c:530)
kern :warn : [ 282.828345] [ T5053] ? __pfx_do_faccessat (fs/open.c:465)
kern :warn : [ 282.828352] [ T5053] ? do_syscall_64 (arch/x86/include/asm/irqflags.h:42 arch/x86/include/asm/irqflags.h:119 include/linux/entry-common.h:108 arch/x86/entry/syscall_64.c:90)
kern :warn : [ 282.828360] [ T5053] do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
kern :warn : [ 282.828364] [ T5053] ? do_syscall_64 (include/linux/irq-entry-common.h:298 include/linux/entry-common.h:196 arch/x86/entry/syscall_64.c:100)
kern :warn : [ 282.828371] [ T5053] ? do_syscall_64 (arch/x86/entry/syscall_64.c:113)
kern :warn : [ 282.828376] [ T5053] ? do_syscall_64 (include/linux/irq-entry-common.h:298 include/linux/entry-common.h:196 arch/x86/entry/syscall_64.c:100)
kern :warn : [ 282.828382] [ T5053] ? do_syscall_64 (arch/x86/entry/syscall_64.c:113)
kern :warn : [ 282.828386] [ T5053] ? __pfx_from_kgid_munged (kernel/user_namespace.c:534)
kern :warn : [ 282.828392] [ T5053] ? do_syscall_64 (include/linux/irq-entry-common.h:298 include/linux/entry-common.h:196 arch/x86/entry/syscall_64.c:100)
kern :warn : [ 282.828396] [ T5053] ? do_syscall_64 (include/linux/irq-entry-common.h:298 include/linux/entry-common.h:196 arch/x86/entry/syscall_64.c:100)
kern :warn : [ 282.828402] [ T5053] ? do_syscall_64 (arch/x86/entry/syscall_64.c:113)
kern :warn : [ 282.828406] [ T5053] ? do_syscall_64 (arch/x86/entry/syscall_64.c:113)
kern :warn : [ 282.828409] [ T5053] ? do_syscall_64 (include/linux/irq-entry-common.h:298 include/linux/entry-common.h:196 arch/x86/entry/syscall_64.c:100)
kern :warn : [ 282.828415] [ T5053] ? do_syscall_64 (arch/x86/entry/syscall_64.c:113)
kern :warn : [ 282.828418] [ T5053] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4629 (discriminator 4))
kern :warn : [ 282.828423] [ T5053] ? clear_bhb_loop (arch/x86/entry/entry_64.S:1549)
kern :warn : [ 282.828430] [ T5053] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:131)
kern :warn : [ 282.828434] [ T5053] RIP: 0033:0x7f5027d8b4aa
kern :warn : [ 282.828458] [ T5053] Code: 73 01 c3 48 8b 0d 4e 59 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 af 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 1e 59 0d 00 f7 d8 64 89 01 48
All code
========
0: 73 01 jae 0x3
2: c3 ret
3: 48 8b 0d 4e 59 0d 00 mov 0xd594e(%rip),%rcx # 0xd5958
a: f7 d8 neg %eax
c: 64 89 01 mov %eax,%fs:(%rcx)
f: 48 83 c8 ff or $0xffffffffffffffff,%rax
13: c3 ret
14: 66 2e 0f 1f 84 00 00 cs nopw 0x0(%rax,%rax,1)
1b: 00 00 00
1e: 66 90 xchg %ax,%ax
20: 49 89 ca mov %rcx,%r10
23: b8 af 01 00 00 mov $0x1af,%eax
28: 0f 05 syscall
2a:* 48 3d 01 f0 ff ff cmp $0xfffffffffffff001,%rax <-- trapping instruction
30: 73 01 jae 0x33
32: c3 ret
33: 48 8b 0d 1e 59 0d 00 mov 0xd591e(%rip),%rcx # 0xd5958
3a: f7 d8 neg %eax
3c: 64 89 01 mov %eax,%fs:(%rcx)
3f: 48 rex.W
Code starting with the faulting instruction
===========================================
0: 48 3d 01 f0 ff ff cmp $0xfffffffffffff001,%rax
6: 73 01 jae 0x9
8: c3 ret
9: 48 8b 0d 1e 59 0d 00 mov 0xd591e(%rip),%rcx # 0xd592e
10: f7 d8 neg %eax
12: 64 89 01 mov %eax,%fs:(%rcx)
15: 48 rex.W
kern :warn : [ 282.828462] [ T5053] RSP: 002b:00007ffde3afb828 EFLAGS: 00000246 ORIG_RAX: 00000000000001af
kern :warn : [ 282.828466] [ T5053] RAX: ffffffffffffffda RBX: 0000561df73281d0 RCX: 00007f5027d8b4aa
kern :warn : [ 282.828469] [ T5053] RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000003
kern :warn : [ 282.828472] [ T5053] RBP: 0000561df7329ca0 R08: 0000000000000000 R09: 0000000000000000
kern :warn : [ 282.828474] [ T5053] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
kern :warn : [ 282.828476] [ T5053] R13: 00007f5027f1d580 R14: 00007f5027f1f26c R15: 00007f5027f04a23
kern :warn : [ 282.828490] [ T5053] </TASK>
kern :info : [ 282.828501] [ T5053] BTRFS info (device nvme0n1p4): bdev /dev/nvme0n1p4 errs: wr 0, rd 0, flush 0, corrupt 3073, gen 0
user :notice: [ 282.829495] [ T979] pfiles = set(dpf.from_package(options.package))
kern :info : [ 282.868038] [ T5053] BTRFS info (device nvme0n1p4): enabling ssd optimizations
kern :info : [ 282.871066] [ T5053] BTRFS info (device nvme0n1p4): turning on async discard
kern :info : [ 282.871071] [ T5053] BTRFS info (device nvme0n1p4): enabling disk space caching
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20260213/202602130950.db059ac8-lkp@intel.com
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
prev parent reply other threads:[~2026-02-13 2:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-05 11:45 [PATCH] btrfs: sink RCU protection to _btrfs_printk() David Sterba
2026-02-09 9:39 ` Filipe Manana
2026-02-09 13:22 ` David Sterba
2026-02-13 2:08 ` kernel test robot [this message]
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