INFO: rcu detected stall in sys_madvise (2)

Status: upstream: reported on 2026/09/26 21:57
Reported-by: syzbot+c014347eaa3518715ac3@syzkaller.appspotmail.com
First crash: 12d, last: 12d
▶ ▼ Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in sys_madvise (2) 1 1 487d 487d 0/3 auto-obsoleted due to no activity on 2025/09/17 02:28
linux-6.6 INFO: rcu detected stall in sys_madvise 1 2 355d 358d 0/2 auto-obsoleted due to no activity on 2026/01/26 08:47
upstream INFO: rcu detected stall in sys_madvise scsi 1 1 1158d 1158d 0/29 auto-obsoleted due to no activity on 2023/11/05 19:10
linux-6.1 INFO: rcu detected stall in sys_madvise 1 1 828d 828d 0/3 auto-obsoleted due to no activity on 2024/10/10 08:27
upstream INFO: rcu detected stall in sys_madvise (2) prio:high mm 1 64 1d10h 404d 0/29 upstream: reported on 2025/08/31 02:33
linux-5.15 INFO: rcu detected stall in sys_madvise 1 1 645d 645d 0/3 auto-obsoleted due to no activity on 2025/04/11 11:19
android-5-15 BUG: soft lockup in sys_madvise 1 1 928d 928d 0/2 auto-obsoleted due to no activity on 2024/06/23 02:57
linux-4.19 BUG: soft lockup in sys_madvise 1 1 1617d 1617d 0/1 auto-obsoleted due to no activity on 2022/09/03 05:10
linux-4.19 BUG: soft lockup in sys_madvise (2) 1 1 1483d 1483d 0/1 auto-obsoleted due to no activity on 2023/01/14 20:18

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5017/1:b..l P5032/1:b..l
	(detected by 0, t=10502 jiffies, g=12845, q=11)
task:rm              state:R  running task     stack:27312 pid: 5032 ppid:  4992 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
 preempt_schedule+0xbc/0xd0 kernel/sched/core.c:6596
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:404 [inline]
 filemap_map_pages+0x10a5/0x1450 mm/filemap.c:3353
 do_fault_around mm/memory.c:4243 [inline]
 do_read_fault mm/memory.c:4258 [inline]
 do_fault mm/memory.c:4392 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x25bb/0x4440 mm/memory.c:4883
 do_user_addr_fault+0x494/0xc90 arch/x86/mm/fault.c:1355
 handle_page_fault arch/x86/mm/fault.c:1443 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f06cba62652
RSP: 002b:00007ffcfd0e2a50 EFLAGS: 00010283
RAX: 0000000000000046 RBX: 00007f06cb6f0270 RCX: 000000000000000a
RDX: 00007f06cb6f0040 RSI: 0000000000000006 RDI: 000000006fffffff
RBP: 00007ffcfd0e2ba0 R08: 0000000000000006 R09: 00000000effffef5
R10: 0000000070000029 R11: 00007ffcfd0e2c88 R12: 0000000000000003
R13: 00007f06cb75c6b0 R14: 00007ffcfd0e2c40 R15: 00007f06cb751018
 </TASK>
task:syz.1.200       state:R  running task     stack:25296 pid: 5017 ppid:  4186 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:435
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:check_region_inline mm/kasan/generic.c:-1 [inline]
RIP: 0010:kasan_check_range+0xb/0x290 mm/kasan/generic.c:189
Code: 31 c0 c3 0f 0b b8 ea ff ff ff c3 0f 0b b8 ea ff ff ff c3 00 00 cc cc 00 00 cc cc 00 00 cc cc b0 01 48 85 f6 0f 84 ac 01 00 00 <55> 41 57 41 56 41 54 53 49 89 f8 49 01 f0 0f 82 0e 02 00 00 49 89
RSP: 0018:ffffc90002eeed58 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff815ced16
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8d8b1ee8
RBP: ffffc90002eeee70 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff94000293717 R12: ffffffff8c31ef60
R13: 1ffff920005dddb8 R14: 0000000000000000 R15: dffffc0000000000
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
 cpumask_test_cpu include/linux/cpumask.h:344 [inline]
 cpu_online include/linux/cpumask.h:895 [inline]
 trace_lock_acquire include/trace/events/lock.h:13 [inline]
 lock_acquire+0xb6/0x400 kernel/locking/lockdep.c:5596
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 page_lock_anon_vma_read+0x1c/0x4a0 mm/rmap.c:538
 rmap_walk_anon_lock mm/rmap.c:2263 [inline]
 rmap_walk_anon+0x71/0x570 mm/rmap.c:2305
 rmap_walk mm/rmap.c:2394 [inline]
 page_referenced+0x495/0x5b0 mm/rmap.c:896
 page_check_references mm/vmscan.c:1243 [inline]
 shrink_page_list+0x1385/0x6de0 mm/vmscan.c:1524
 reclaim_pages+0x712/0x990 mm/vmscan.c:2424
 madvise_cold_or_pageout_pte_range+0x1650/0x1ea0 mm/madvise.c:387
 walk_pmd_range mm/pagewalk.c:128 [inline]
 walk_pud_range mm/pagewalk.c:205 [inline]
 walk_p4d_range mm/pagewalk.c:240 [inline]
 walk_pgd_range+0xb28/0x1370 mm/pagewalk.c:277
 __walk_page_range+0x136/0x590 mm/pagewalk.c:379
 walk_page_range+0x3a3/0x550 mm/pagewalk.c:477
 madvise_pageout_page_range mm/madvise.c:531 [inline]
 madvise_pageout mm/madvise.c:567 [inline]
 madvise_vma mm/madvise.c:997 [inline]
 do_madvise+0x16a6/0x2aa0 mm/madvise.c:1206
 __do_sys_madvise mm/madvise.c:1232 [inline]
 __se_sys_madvise mm/madvise.c:1230 [inline]
 __x64_sys_madvise+0xa2/0xb0 mm/madvise.c:1230
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1ddac83159
RSP: 002b:00007f1dd8edb028 EFLAGS: 00000246 ORIG_RAX: 000000000000001c
RAX: ffffffffffffffda RBX: 00007f1ddaf0afa0 RCX: 00007f1ddac83159
RDX: 0000000000000015 RSI: 000000000080fd00 RDI: 000020000042f000
RBP: 00007f1ddad1a06b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1ddaf0b038 R14: 00007f1ddaf0afa0 R15: 00007ffca3c33708
 </TASK>
rcu: rcu_preempt kthread starved for 10500 jiffies! g12845 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:26896 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11f0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 5035 Comm: syz.2.208 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x1110/0x1270 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x845/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:show_all_irqs fs/proc/stat.c:-1 [inline]
RIP: 0010:show_stat+0x16a0/0x1970 fs/proc/stat.c:197
Code: 66 44 75 ff 89 c3 48 b8 00 00 00 00 00 fc ff df 41 0f b6 04 04 84 c0 75 1c 44 8b 35 7a c8 45 0a 44 39 f3 73 39 e8 10 6b 8d ff <45> 89 fe 41 89 df e9 60 ff ff ff 48 c7 c1 00 72 31 8c 80 e1 07 80
RSP: 0018:ffffc900031bf5e0 EFLAGS: 00000246
RAX: ffffffff81eba990 RBX: 0000000000000021 RCX: 0000000000080000
RDX: ffffc9000ea2d000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc900031bf878 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff52000637e9f R12: 1ffffffff1862e40
R13: ffff88807ce63de0 R14: 00000000000001b8 R15: 0000000000000021
 seq_read_iter+0x460/0xc50 fs/seq_file.c:230
 call_read_iter include/linux/fs.h:2173 [inline]
 generic_file_splice_read+0x3ed/0x5f0 fs/splice.c:311
 do_splice_to fs/splice.c:807 [inline]
 splice_direct_to_actor+0x41f/0xc00 fs/splice.c:881
 do_splice_direct+0x1d4/0x2f0 fs/splice.c:1008
 do_sendfile+0x524/0xe30 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1317 [inline]
 __se_sys_sendfile64+0x141/0x1a0 fs/read_write.c:1303
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7ff283d48159
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:00007ff281f7f028 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007ff283fd0090 RCX: 00007ff283d48159
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000005
RBP: 00007ff283ddf06b R08: 0000000000000000 R09: 0000000000000000
R10: 0000020000023896 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff283fd0128 R14: 00007ff283fd0090 R15: 00007ffd924988f8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/26 21:57 linux-5.15.y 0248c33e835e a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_madvise
* Struck through repros no longer work on HEAD.