syzbot


INFO: rcu detected stall in generic_file_write_iter (2)

Status: upstream: reported on 2024/12/19 01:50
Reported-by: syzbot+8fe6306e202244fa432b@syzkaller.appspotmail.com
First crash: 149d, last: 29d
Similar bugs (12)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in generic_file_write_iter (3) kernel 1 1991d 1991d 0/28 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in generic_file_write_iter (2) exfat 2 2206d 2245d 0/28 auto-closed as invalid on 2019/10/25 09:01
upstream BUG: soft lockup in generic_file_write_iter (2) mm 8 677d 665d 0/28 auto-obsoleted due to no activity on 2023/10/18 13:34
linux-5.15 INFO: rcu detected stall in generic_file_write_iter (2) 24 26d 435d 0/3 upstream: reported on 2024/03/08 18:29
linux-5.15 INFO: rcu detected stall in generic_file_write_iter 1 621d 621d 0/3 auto-obsoleted due to no activity on 2023/12/13 17:16
upstream INFO: rcu detected stall in generic_file_write_iter (4) cgroups 1 1924d 1920d 0/28 auto-closed as invalid on 2020/05/09 11:43
upstream BUG: soft lockup in generic_file_write_iter net 2 863d 897d 0/28 auto-obsoleted due to no activity on 2023/04/05 19:12
upstream INFO: rcu detected stall in generic_file_write_iter mm 58 2269d 2412d 0/28 closed as dup on 2018/10/27 15:28
upstream INFO: rcu detected stall in generic_file_write_iter (5) fs 2 1758d 1765d 0/28 auto-closed as invalid on 2020/10/22 01:02
upstream INFO: rcu detected stall in generic_file_write_iter (6) cgroups mm 2 1244d 1301d 0/28 closed as invalid on 2022/02/08 09:50
linux-6.1 INFO: rcu detected stall in generic_file_write_iter 18 278d 391d 0/3 auto-obsoleted due to no activity on 2024/11/12 08:46
android-5-15 BUG: soft lockup in generic_file_write_iter 1 370d 370d 0/2 auto-obsoleted due to no activity on 2024/08/10 08:10

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5762/1:b..l
	(detected by 0, t=10502 jiffies, g=18705, q=39 ncpus=2)
task:syz.0.393       state:R  running task     stack:24856 pid:5762  ppid:4268   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6561
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6873
 irqentry_exit+0x53/0x80 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666
Code: 2b 00 74 08 4c 89 f7 e8 2f 44 77 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc9000584f420 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff92000b09e90 RCX: 1ffff92000b09e30
RDX: dffffc0000000000 RSI: ffffffff8b0c1dc0 RDI: ffffffff8b5f5fe0
RBP: ffffc9000584f580 R08: dffffc0000000000 R09: fffffbfff225704d
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000b09e8c
R13: dffffc0000000000 R14: ffffc9000584f480 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 percpu_ref_get_many+0x36/0x140 include/linux/percpu-refcount.h:202
 percpu_ref_get include/linux/percpu-refcount.h:222 [inline]
 css_get include/linux/cgroup.h:327 [inline]
 charge_memcg+0x152/0x3f0 mm/memcontrol.c:6929
 __mem_cgroup_charge+0x23/0x80 mm/memcontrol.c:6946
 mem_cgroup_charge include/linux/memcontrol.h:672 [inline]
 shmem_add_to_page_cache+0xaa6/0x1e60 mm/shmem.c:708
 shmem_get_folio_gfp+0x164e/0x3470 mm/shmem.c:1971
 shmem_get_folio mm/shmem.c:2072 [inline]
 shmem_write_begin+0x16e/0x4e0 mm/shmem.c:2556
 generic_perform_write+0x2fc/0x5e0 mm/filemap.c:3845
 __generic_file_write_iter+0x176/0x400 mm/filemap.c:3973
 generic_file_write_iter+0xab/0x310 mm/filemap.c:4005
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x857/0xbc0 fs/read_write.c:584
 ksys_write+0x19c/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0x80 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb6afd8cc1f
RSP: 002b:00007fb6b0c49df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007fb6afd8cc1f
RDX: 0000000001000000 RSI: 00007fb6a55f7000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000009861
R10: 000020000001c942 R11: 0000000000000293 R12: 0000000000000003
R13: 00007fb6b0c49ef0 R14: 00007fb6b0c49eb0 R15: 00007fb6a55f7000
 </TASK>
rcu: rcu_preempt kthread starved for 10543 jiffies! g18705 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:26712 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6561
 schedule+0xbf/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.1.134-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:736
Code: ff ff ff 4c 89 ff e8 74 7f 26 f7 e9 0a ff ff ff e8 2a a6 f5 ff 00 00 cc cc 00 00 cc cc 00 00 66 90 0f 00 2d 47 7c 4b 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0018:ffffffff8d007d68 EFLAGS: 000002c2
RAX: e338929b1dc7d500 RBX: ffffffff8abb3207 RCX: 00000000003f8799
RDX: 0000000000000001 RSI: ffffffff8b0c0c40 RDI: ffffffff8b5f5fe0
RBP: ffffffff8d007ec0 R08: dffffc0000000000 R09: ffffed10171c6ad6
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 1ffffffff1a00fc6 R14: 0000000000000000 R15: 1ffffffff1a17b30
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000004000 CR3: 000000005beb3000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 default_idle_call+0x84/0xc0 kernel/sched/idle.c:109
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x251/0x680 kernel/sched/idle.c:303
 cpu_startup_entry+0x3d/0x60 kernel/sched/idle.c:401
 rest_init+0x2da/0x300 init/main.c:733
 arch_call_rest_init+0xa/0xa init/main.c:893
 start_kernel+0x496/0x53f init/main.c:1140
 secondary_startup_64_no_verify+0xcf/0xdb
 </TASK>
vkms_vblank_simulate: vblank timer overrun

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/17 21:02 linux-6.1.y 420102835862 229db4cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in generic_file_write_iter
2025/04/02 11:35 linux-6.1.y 8e60a714ba3b c799dfdd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in generic_file_write_iter
2025/03/23 05:33 linux-6.1.y 344a09659766 4e8d3850 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in generic_file_write_iter
2025/01/28 00:13 linux-6.1.y 75cefdf153f5 18070896 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in generic_file_write_iter
2024/12/19 01:49 linux-6.1.y 52f863f820fd 1432fc84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in generic_file_write_iter
* Struck through repros no longer work on HEAD.