INFO: rcu detected stall in filemap_fault (4)

Status: upstream: reported syz repro on 2026/10/17 23:42
Subsystems: mm
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+af37a78f810994eae641@syzkaller.appspotmail.com
First crash: 465d, last: 9h43m
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ID Workflow Result Correct Bug Created Started Finished Revision
4ecc9503 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ✅ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ INFO: rcu detected stall in filemap_fault (4) 2026/05/30 11:38 2026/05/30 11:38 2026/05/30 12:36 6b4a8443
ca0d788a assessment-security 💥 INFO: rcu detected stall in filemap_fault (4) 2026/05/14 10:02 2026/05/14 10:02 2026/05/14 10:05 6ccb967e
80f2f116 repro ❓ INFO: rcu detected stall in filemap_fault (4) 2026/03/06 09:44 2026/03/06 09:44 2026/03/06 09:54 31e9c887
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Title Replies (including bot) Last reply
[syzbot] [mm?] INFO: rcu detected stall in filemap_fault (4) 1 (2) 2026/10/18 04:37
▶ ▼ Similar bugs (10)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in filemap_fault (4) origin:lts-only 1 syz, C error 4 63d 99d 0/3 upstream: reported C repro on 2026/07/11 16:44
linux-6.6 INFO: rcu detected stall in filemap_fault 1 1 196d 196d 0/2 auto-obsoleted due to no activity on 2026/07/14 16:51
upstream INFO: rcu detected stall in filemap_fault (3) mm 1 13 563d 843d 0/29 auto-obsoleted due to no activity on 2025/07/02 21:11
upstream INFO: rcu detected stall in filemap_fault mm 1 1 2933d 2931d 0/29 closed as dup on 2019/01/02 16:20
upstream INFO: rcu detected stall in filemap_fault (2) fs mm 1 7 1804d 1824d 0/29 auto-closed as invalid on 2022/02/07 21:39
linux-5.15 INFO: rcu detected stall in filemap_fault (3) 1 1 390d 390d 0/3 auto-obsoleted due to no activity on 2026/01/01 14:26
linux-6.1 INFO: rcu detected stall in filemap_fault (2) 1 1 31d 31d 0/3 upstream: reported on 2026/09/17 20:37
linux-5.15 INFO: rcu detected stall in filemap_fault (2) 1 4 494d 598d 0/3 auto-obsoleted due to no activity on 2025/09/19 16:02
linux-6.1 INFO: rcu detected stall in filemap_fault 1 2 763d 772d 0/3 auto-obsoleted due to no activity on 2024/12/24 06:37
linux-5.15 INFO: rcu detected stall in filemap_fault 1 2 785d 788d 0/3 auto-obsoleted due to no activity on 2024/12/02 14:29

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-0): P5320/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=61125, q=864 ncpus=1)
task:syz-execprog    state:R  running task     stack:22864 pid:5320  tgid:5314  ppid:5313   task_flags:0x440040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x17db/0x58f0 kernel/sched/core.c:7284
 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7606
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
 irqentry_exit+0x14f/0x920 kernel/entry/common.c:167
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:task_css include/linux/cgroup.h:548 [inline]
RIP: 0010:mem_cgroup_from_task+0x8f/0x120 mm/memcontrol.c:1134
Code: 38 48 c7 c7 58 c8 d9 8f be ff ff ff ff e8 a9 1a a8 09 85 c0 75 23 49 83 c6 2c 4c 89 f0 48 c1 e8 03 42 0f b6 04 38 84 c0 75 6e <41> f6 06 04 75 09 e8 76 f7 68 ff 85 c0 74 28 48 83 c3 20 48 89 d8
RSP: 0018:ffffc9000e0ef610 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffff8fd9f0c0 RCX: 0000000000000046
RDX: 000000009a0f617f RSI: ffffffff8e6f5004 RDI: ffffffff8c6dec80
RBP: 1ffff110061db463 R08: ffffffff8242ae78 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed10070f1e47 R12: ffff88803878f230
R13: dffffc0000000000 R14: ffff888000f525ac R15: dffffc0000000000
 get_mem_cgroup_from_mm+0xd6/0x290 mm/memcontrol.c:1187
 __mem_cgroup_charge+0x15/0x80 mm/memcontrol.c:5226
 mem_cgroup_charge include/linux/memcontrol.h:662 [inline]
 filemap_add_folio+0x140/0x4e0 mm/filemap.c:965
 page_cache_ra_unbounded+0x46d/0x9d0 mm/readahead.c:293
 do_page_cache_ra mm/readahead.c:348 [inline]
 page_cache_ra_order+0xb47/0xee0 mm/readahead.c:558
 do_sync_mmap_readahead+0x75e/0x990 mm/filemap.c:3443
 filemap_fault+0x7d9/0x13b0 mm/filemap.c:3597
 __do_fault+0x138/0x2a0 mm/memory.c:5565
 do_read_fault mm/memory.c:6000 [inline]
 do_fault mm/memory.c:6134 [inline]
 do_pte_missing+0x2215/0x34b0 mm/memory.c:4700
 handle_pte_fault mm/memory.c:6558 [inline]
 __handle_mm_fault mm/memory.c:6707 [inline]
 handle_mm_fault+0x1a53/0x3750 mm/memory.c:6876
 do_user_addr_fault+0xa4f/0x1340 arch/x86/mm/fault.c:1343
 handle_page_fault arch/x86/mm/fault.c:1483 [inline]
 exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1536
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595
RIP: 0033:0x46fe0e
RSP: 002b:000010e09c0a5178 EFLAGS: 00010216
RAX: 00000000015e4970 RBX: 000000000173a820 RCX: 0000000000000000
RDX: 000000000001a058 RSI: 00000000015ca918 RDI: 000000000041db80
RBP: 000010e09c0a51a0 R08: 00000000015ca918 R09: 00000000015cb3b8
R10: 0000000001911ec0 R11: 0000000000000000 R12: 0000000043fdf3b9
R13: 0000000000000000 R14: 000010e09c078960 R15: 000000000000012a
 </TASK>
rcu: rcu_preempt kthread starved for 1643 jiffies! g61125 f0x0 RCU_GP_WAIT_FQS(5) ->state=I ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:I stack:27496 pid:17    tgid:17    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x17db/0x58f0 kernel/sched/core.c:7284
 preempt_schedule_common+0x7f/0xd0 kernel/sched/core.c:7463
 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:211 [inline]
 _raw_spin_unlock_irqrestore+0x76/0x80 kernel/locking/spinlock.c:221
 debug_object_assert_init+0x20d/0x380 lib/debugobjects.c:1072
 debug_timer_assert_init kernel/time/timer.c:803 [inline]
 debug_assert_init kernel/time/timer.c:848 [inline]
 __mod_timer+0x4b/0xed0 kernel/time/timer.c:1025
 schedule_timeout+0x14d/0x2c0 kernel/time/sleep_timeout.c:98
 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122
 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 5761 Comm: syz.2.24 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x80 kernel/kcov.c:212
Code: 8b 3d 34 de ab 0c 48 89 de 5b e9 93 fc 66 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d c8 9d ce 12 65 48 8b 15 c8 9d ce 12 f7 c2 00 01 00 ff
RSP: 0018:ffffc9000d3278e8 EFLAGS: 00000202
RAX: ffffffff8be56f10 RBX: 1ffff11006b094a2 RCX: ffff888034c90000
RDX: ffff88803584a508 RSI: ffff88803584a508 RDI: ffffc9000d327ab8
RBP: 1ffff11006b094a1 R08: ffff888034c9001b R09: 1ffff11006992003
R10: dffffc0000000000 R11: ffffed1006992004 R12: ffff88803584a508
R13: ffff88803584a508 R14: ffff88803584a508 R15: ffff88803584a510
FS:  00007f0baa9bd6c0(0000) GS:ffff88808b0b4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 000000004004c000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __list_add include/linux/list.h:172 [inline]
 list_add_tail include/linux/list.h:206 [inline]
 plist_add+0x420/0x580 lib/plist.c:111
 __futex_queue+0xed/0x160 kernel/futex/core.c:866
 futex_queue kernel/futex/futex.h:333 [inline]
 futex_wait_setup+0x424/0x590 kernel/futex/waitwake.c:695
 __futex_wait+0x15f/0x400 kernel/futex/waitwake.c:717
 futex_wait+0x121/0x390 kernel/futex/waitwake.c:750
 do_futex+0x3e7/0x4e0 kernel/futex/syscalls.c:133
 __do_sys_futex kernel/futex/syscalls.c:210 [inline]
 __se_sys_futex+0x3a8/0x450 kernel/futex/syscalls.c:191
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0ba9b9e559
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0baa9bd0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f0ba9e25fa8 RCX: 00007f0ba9b9e559
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f0ba9e25fa8
RBP: 00007f0ba9e25fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0ba9e26038 R14: 00007ffe158db450 R15: 00007ffe158db538
 </TASK>

Crashes (34):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/17 10:42 upstream 70dd4ee72eb2 432c0077 .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root INFO: rcu detected stall in filemap_fault
2026/10/17 07:55 upstream 70dd4ee72eb2 432c0077 .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root INFO: rcu detected stall in filemap_fault
2026/10/18 13:12 upstream 32c52ec87d62 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in filemap_fault
2026/10/18 06:35 upstream 58161ead29e5 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in filemap_fault
2026/10/02 16:42 upstream ce1e0223d8ad 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in filemap_fault
2026/09/15 13:08 upstream 587858367581 81a27d1a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in filemap_fault
2026/09/06 14:05 upstream 1fc5a74b108f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in filemap_fault
2026/07/16 07:25 upstream 58717b2a1365 27a8bd60 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in filemap_fault
2026/04/24 16:59 upstream dd6c438c3e64 629ff21a .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in filemap_fault
2026/04/22 01:35 upstream 4ee64205ffaa 9765efe0 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in filemap_fault
2026/04/13 07:05 upstream 028ef9c96e96 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in filemap_fault
2026/04/11 16:05 upstream e774d5f1bc27 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in filemap_fault
2026/04/04 09:03 upstream 631919fb12fe 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in filemap_fault
2026/04/03 15:57 upstream d8a9a4b11a13 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in filemap_fault
2026/03/21 09:24 upstream 42bddab0563f 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in filemap_fault
2026/03/05 06:18 upstream ecc64d2dc9ff a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in filemap_fault
2026/03/03 13:20 upstream af4e9ef3d784 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in filemap_fault
2026/01/06 11:37 upstream 7f98ab9da046 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in filemap_fault
2025/12/27 01:10 upstream 3f0e9c8cefa9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in filemap_fault
2025/12/23 23:22 upstream b927546677c8 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in filemap_fault
2025/12/16 18:09 upstream 40fbbd64bba6 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in filemap_fault
2025/12/13 03:07 upstream 187d0801404f d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in filemap_fault
2025/11/27 10:35 upstream 4941a17751c9 e8331348 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in filemap_fault
2025/11/23 07:55 upstream 89edd36fd801 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in filemap_fault
2025/11/07 16:47 upstream 4a0c9b339199 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in filemap_fault
2025/10/06 00:12 upstream 6093a688a07d 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in filemap_fault
2025/08/12 22:20 upstream 53e760d89498 c06e8995 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in filemap_fault
2025/07/10 06:11 upstream 8c2e52ebbe88 956bd956 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in filemap_fault
2026/03/12 15:12 upstream 80234b5ab240 4efadf07 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: rcu detected stall in filemap_fault
2026/07/20 18:31 net e13caf1c2658 de6a700d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in filemap_fault
2026/10/13 23:32 linux-next 1fffefb00cc0 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: rcu detected stall in filemap_fault
2025/11/29 03:38 linux-next 7d31f578f323 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in filemap_fault
2026/06/24 05:01 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 92e3f6ef4ffb 042555ff .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: rcu detected stall in filemap_fault
2026/06/12 02:58 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 596d152bc5e3 e93da63e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: rcu detected stall in filemap_fault
* Struck through repros no longer work on HEAD.