ci2 starts bisection 2026-08-16 15:49:36.178876802 +0000 UTC m=+143928.177114913
bisecting fixing commit since c86c4726e7f044ab73b493c6f00527aafef640cd
building syzkaller on d78ea535f456172a095a6d211ee0a2de1d049968
ensuring issue is reproducible on original commit c86c4726e7f044ab73b493c6f00527aafef640cd

testing commit c86c4726e7f044ab73b493c6f00527aafef640cd gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: 2fa7cc478552bbc28de583d6764c6efec3dd58f02ebc889991c368fff647a4fc
run #0: basic kernel testing failed: WARNING in process_one_work
run #1: crashed: INFO: rcu detected stall in batadv_nc_worker
run #2: crashed: INFO: rcu detected stall in corrupted
run #3: crashed: INFO: rcu detected stall in batadv_nc_worker
run #4: crashed: INFO: rcu detected stall in batadv_nc_worker
run #5: crashed: INFO: rcu detected stall in filemap_fault
run #6: crashed: INFO: rcu detected stall in sys_mlock
run #7: crashed: INFO: rcu detected stall in batadv_nc_worker
run #8: crashed: INFO: rcu detected stall in sys_mlock
run #9: crashed: INFO: rcu detected stall in batadv_nc_worker
run #10: crashed: INFO: rcu detected stall in corrupted
run #11: crashed: INFO: rcu detected stall in corrupted
run #12: crashed: INFO: rcu detected stall in corrupted
run #13: crashed: INFO: rcu detected stall in sys_mlock
run #14: crashed: INFO: rcu detected stall in batadv_nc_worker
run #15: crashed: INFO: rcu detected stall in sys_mlock
run #16: crashed: INFO: rcu detected stall in corrupted
run #17: crashed: INFO: rcu detected stall in vm_area_alloc
run #18: crashed: INFO: rcu detected stall in security_file_open
run #19: crashed: INFO: rcu detected stall in gc_worker
representative crash: INFO: rcu detected stall in batadv_nc_worker, types: [HANG]
check whether we can drop unnecessary instrumentation
disabling configs for [memleak ubsan bug_or_warning kasan locking atomic_sleep], they are not needed
testing commit c86c4726e7f044ab73b493c6f00527aafef640cd gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: ebcc7fbb85cbe99d421f14e797be15a1097346952efe63b4370fc442ae7f2402
run #0: crashed: INFO: rcu detected stall in corrupted
run #1: crashed: INFO: rcu detected stall in filemap_fault
run #2: crashed: INFO: rcu detected stall in corrupted
run #3: crashed: INFO: rcu detected stall in corrupted
run #4: crashed: INFO: rcu detected stall in sys_mlock
run #5: crashed: INFO: rcu detected stall in sys_mlock
run #6: crashed: INFO: rcu detected stall in filemap_fault
run #7: crashed: INFO: rcu detected stall in sys_mlock
run #8: crashed: INFO: rcu detected stall in corrupted
run #9: crashed: INFO: rcu detected stall in filemap_fault
representative crash: INFO: rcu detected stall in corrupted, types: [HANG]
the bug reproduces without the instrumentation
disabling configs for [ubsan bug_or_warning kasan locking atomic_sleep memleak], they are not needed
kconfig minimization: base=3707 full=7426 leaves diff=2100
split chunks (needed=false): <2100>
split chunk #0 of len 2100 into 5 parts
testing without sub-chunk 1/5
disabling configs for [ubsan bug_or_warning kasan locking atomic_sleep memleak], they are not needed
testing commit c86c4726e7f044ab73b493c6f00527aafef640cd gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: 8a46c296ba06571fa196388648adafd0904c417d5bb3150f5d9dede17d14719f
run #0: crashed: INFO: rcu detected stall in sys_mlock
run #1: crashed: INFO: rcu detected stall in corrupted
run #2: crashed: INFO: rcu detected stall in filemap_fault
run #3: crashed: INFO: rcu detected stall in sys_mlock
run #4: crashed: INFO: rcu detected stall in corrupted
run #5: crashed: INFO: rcu detected stall in filemap_fault
run #6: crashed: INFO: rcu detected stall in filemap_fault
run #7: crashed: INFO: rcu detected stall in corrupted
run #8: crashed: INFO: rcu detected stall in corrupted
run #9: crashed: INFO: rcu detected stall in filemap_fault
representative crash: INFO: rcu detected stall in sys_mlock, types: [HANG]
the chunk can be dropped
testing without sub-chunk 2/5
disabling configs for [memleak ubsan bug_or_warning kasan locking atomic_sleep], they are not needed
testing commit c86c4726e7f044ab73b493c6f00527aafef640cd gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: cadabe994814dd632baed3ad5fc4ac96ec0023f96b0daa5a0c210c64899bfbce
run #0: crashed: INFO: rcu detected stall in filemap_fault
run #1: crashed: INFO: rcu detected stall in sys_mlock
run #2: crashed: INFO: rcu detected stall in corrupted
run #3: crashed: INFO: rcu detected stall in filemap_fault
run #4: crashed: INFO: rcu detected stall in sys_openat
run #5: crashed: INFO: rcu detected stall in corrupted
run #6: crashed: INFO: rcu detected stall in sys_mlock
run #7: crashed: INFO: rcu detected stall in corrupted
run #8: crashed: INFO: rcu detected stall in sys_mlock
run #9: crashed: INFO: rcu detected stall in sys_mlock
representative crash: INFO: rcu detected stall in filemap_fault, types: [HANG]
the chunk can be dropped
testing without sub-chunk 3/5
disabling configs for [locking atomic_sleep memleak ubsan bug_or_warning kasan], they are not needed
testing commit c86c4726e7f044ab73b493c6f00527aafef640cd gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: f65e8b44d9c6c50aa217dd3d936f0bfbd4d96158c9710d4f64a64cd9f32f7a87
run #0: crashed: INFO: rcu detected stall in corrupted
run #1: crashed: INFO: rcu detected stall in filemap_fault
run #2: crashed: INFO: rcu detected stall in corrupted
run #3: crashed: INFO: rcu detected stall in sys_mlock
run #4: crashed: INFO: rcu detected stall in corrupted
run #5: crashed: INFO: rcu detected stall in filemap_fault
run #6: crashed: INFO: rcu detected stall in filemap_fault
run #7: crashed: INFO: rcu detected stall in corrupted
run #8: crashed: INFO: rcu detected stall in filemap_fault
run #9: crashed: INFO: rcu detected stall in sys_mlock
representative crash: INFO: rcu detected stall in corrupted, types: [HANG]
the chunk can be dropped
testing without sub-chunk 4/5
disabling configs for [atomic_sleep memleak ubsan bug_or_warning kasan locking], they are not needed
testing commit c86c4726e7f044ab73b493c6f00527aafef640cd gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: 6afb243906c134a174c82efec0cf04251be1226e9c30b149d36c09c30f4cc1d0
run #0: crashed: INFO: rcu detected stall in sys_mlock
run #1: crashed: INFO: rcu detected stall in corrupted
run #2: crashed: INFO: rcu detected stall in sys_mlock
run #3: crashed: INFO: rcu detected stall in sys_mlock
run #4: crashed: INFO: rcu detected stall in sys_mlock
run #5: crashed: INFO: rcu detected stall in filemap_fault
run #6: crashed: INFO: rcu detected stall in sys_mlock
run #7: crashed: INFO: rcu detected stall in sys_mlock
run #8: crashed: INFO: rcu detected stall in sys_mlock
run #9: crashed: INFO: rcu detected stall in corrupted
representative crash: INFO: rcu detected stall in sys_mlock, types: [HANG]
the chunk can be dropped
testing without sub-chunk 5/5
disabling configs for [memleak ubsan bug_or_warning kasan locking atomic_sleep], they are not needed
testing commit c86c4726e7f044ab73b493c6f00527aafef640cd gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: 14cc4263033940d45a4c251463e274f388b381a4a74f160f20a76fceda3845d8
run #0: crashed: INFO: rcu detected stall in filemap_fault
run #1: crashed: INFO: rcu detected stall in corrupted
run #2: crashed: INFO: rcu detected stall in sys_mlock
run #3: crashed: INFO: rcu detected stall in filemap_fault
run #4: crashed: INFO: rcu detected stall in filemap_fault
run #5: crashed: INFO: rcu detected stall in sys_mlock
run #6: crashed: INFO: rcu detected stall in filemap_fault
run #7: crashed: INFO: rcu detected stall in filemap_fault
run #8: crashed: INFO: rcu detected stall in filemap_fault
run #9: crashed: INFO: rcu detected stall in sys_mlock
representative crash: INFO: rcu detected stall in filemap_fault, types: [HANG]
the chunk can be dropped
disabling configs for [memleak ubsan bug_or_warning kasan locking atomic_sleep], they are not needed
testing current HEAD aabd761612dbeb7d40750d485da219d11433718a
testing commit aabd761612dbeb7d40750d485da219d11433718a gcc
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.44
kernel signature: 77dc4467e86ad8c230cc90d67db8d1bb1e2c622fdef858c719dab28eebc0e59e
run #0: crashed: INFO: rcu detected stall in sys_mlock
run #1: crashed: INFO: rcu detected stall in filemap_fault
run #2: crashed: INFO: rcu detected stall in sys_mlock
run #3: crashed: INFO: rcu detected stall in filemap_fault
run #4: crashed: INFO: rcu detected stall in filemap_fault
run #5: crashed: INFO: rcu detected stall in corrupted
run #6: crashed: INFO: rcu detected stall in filemap_fault
run #7: crashed: INFO: rcu detected stall in sys_mlock
run #8: crashed: INFO: rcu detected stall in corrupted
run #9: crashed: INFO: rcu detected stall in sys_mlock
representative crash: INFO: rcu detected stall in sys_mlock, types: [HANG]
crash still not fixed/happens on the oldest tested release
revisions tested: 8, total time: 2h15m59.937923903s (build: 41m14.788222227s, test: 1h17m28.184735963s)
crash still not fixed or there were kernel test errors
commit msg: Linux 5.15.215
crash: INFO: rcu detected stall in sys_mlock
rcu: INFO: rcu_sched self-detected stall on CPU
rcu: 	0-...!: (1 GPs behind) idle=349/1/0x4000000000000000 softirq=3468/3502 fqs=1 
	(t=10001 jiffies g=1265 q=106)
rcu: rcu_sched kthread timer wakeup didn't happen for 9999 jiffies! g1265 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=622
rcu: rcu_sched kthread starved for 10002 jiffies! g1265 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: 	Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_sched       state:I stack:14376 pid:   12 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x2b8/0x790 kernel/sched/core.c:6395
 schedule+0x53/0x90 kernel/sched/core.c:6478
 schedule_timeout+0xaf/0x140 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0xe2/0x320 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x77/0xe0 kernel/rcu/tree.c:2145
 kthread+0x10b/0x130 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 246 Comm: kworker/u4:3 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_many_cond+0xcd/0x280 kernel/smp.c:969
Code: 32 48 89 ee e8 94 05 3a 00 3b 05 c2 92 7b 01 89 c7 73 20 48 63 c7 49 8b 16 48 03 14 c5 c0 78 3c 82 8b 42 08 a8 01 74 09 f3 90 <8b> 42 08 a8 01 75 f7 eb ce 48 83 c4 48 5b 5d 41 5c 41 5d 41 5e 41
RSP: 0018:ffffc90000ab36c8 EFLAGS: 00000202
RAX: 0000000000000011 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff888237c32480 RSI: ffff888237d2bd48 RDI: 0000000000000000
RBP: ffff888237d2bd48 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: fff00000001fffff R12: ffff888237d2a440
R13: ffff888237d2bd40 R14: ffff888237d2bd40 R15: 0000000000032480
FS:  0000000000000000(0000) GS:ffff888237d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000075000 CR3: 000000010cb9d000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x19/0x20 kernel/smp.c:1134
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:87 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:946 [inline]
 flush_tlb_mm_range+0xdf/0x130 arch/x86/mm/tlb.c:1034
 flush_tlb_page arch/x86/include/asm/tlbflush.h:240 [inline]
 ptep_clear_flush+0x43/0x50 mm/pgtable-generic.c:97
 page_mkclean_one+0x9c/0x100 mm/rmap.c:938
 rmap_walk_file+0x11d/0x270 mm/rmap.c:2378
 rmap_walk mm/rmap.c:2396 [inline]
 page_mkclean+0xcb/0x100 mm/rmap.c:1006
 clear_page_dirty_for_io+0xb5/0x250 mm/page-writeback.c:2749
 mpage_submit_page+0x1a/0x60 fs/ext4/inode.c:2095
 mpage_process_page_bufs+0xfc/0x110 fs/ext4/inode.c:2229
 mpage_prepare_extent_to_map+0x21f/0x3f0 fs/ext4/inode.c:2657
 ext4_writepages+0x257/0x10d0 fs/ext4/inode.c:2785
 do_writepages+0x116/0x1e0 mm/page-writeback.c:2386
 __writeback_single_inode+0x42/0x310 fs/fs-writeback.c:1657
 writeback_sb_inodes+0x210/0x530 fs/fs-writeback.c:1940
 __writeback_inodes_wb+0x47/0xe0 fs/fs-writeback.c:2011
 wb_writeback+0x248/0x2d0 fs/fs-writeback.c:2116
 wb_check_old_data_flush fs/fs-writeback.c:2216 [inline]
 wb_do_writeback fs/fs-writeback.c:2269 [inline]
 wb_workfn+0x2c5/0x4f0 fs/fs-writeback.c:2298
 process_one_work+0x252/0x440 kernel/workqueue.c:2310
 worker_thread+0x4d/0x330 kernel/workqueue.c:2457
 kthread+0x10b/0x130 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
NMI backtrace for cpu 0
CPU: 0 PID: 3529 Comm: syz.7.30 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x41/0x5e lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x32/0x80 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x81/0x90 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_dump_cpu_stacks+0xa5/0xd3 kernel/rcu/tree_stall.h:349
 print_cpu_stall kernel/rcu/tree_stall.h:633 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq.cold+0xc7/0x1e7 kernel/rcu/tree.c:2619
 update_process_times+0x87/0xc0 kernel/time/timer.c:2021
 tick_sched_handle+0x1d/0x50 kernel/time/tick-sched.c:254
 tick_sched_timer+0x5c/0x70 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x11c/0x290 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x109/0x230 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x63/0x100 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x65/0x90 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:lock_acquire+0xb7/0x130 kernel/locking/lockdep.c:5627
Code: ef e8 7d f6 ff ff b8 ff ff ff ff 48 83 c4 18 65 0f c1 05 b4 fa f5 7e 83 f8 01 75 6f 9c 58 f6 c4 02 75 61 4d 85 ff 74 01 fb 5b <5d> 41 5c 41 5d 41 5e 41 5f c3 65 8b 05 18 98 f5 7e 89 c0 48 0f a3
RSP: 0018:ffffc90001997c30 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffc90001997d10 RCX: 00000000bc80c055
RDX: 00000000e23efd5e RSI: 000000008680c613 RDI: 0000000035fffa42
RBP: ffffffff82775300 R08: 0000000000020015 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000008 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000200
 rcu_lock_acquire include/linux/rcupdate.h:313 [inline]
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 filemap_map_pages+0x9b/0x4a0 mm/filemap.c:3313
 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+0xabe/0xd00 mm/memory.c:4785
 handle_mm_fault+0xfa/0x290 mm/memory.c:4883
 faultin_page mm/gup.c:976 [inline]
 __get_user_pages+0x24a/0x620 mm/gup.c:1197
 populate_vma_page_range+0xb2/0xf0 mm/gup.c:1529
 __mm_populate+0xa4/0x180 mm/gup.c:1638
 do_mlock+0x103/0x250 mm/mlock.c:688
 __do_sys_mlock mm/mlock.c:696 [inline]
 __se_sys_mlock mm/mlock.c:694 [inline]
 __x64_sys_mlock+0x12/0x20 mm/mlock.c:694
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x33/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc5c2a42e59
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:00007fc5c28a4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000095
RAX: ffffffffffffffda RBX: 00007fc5c2ccafa0 RCX: 00007fc5c2a42e59
RDX: 0000000000000000 RSI: 0000000000800000 RDI: 0000200000000000
RBP: 00007fc5c2ad8e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc5c2ccb038 R14: 00007fc5c2ccafa0 R15: 00007fffa798b858
 </TASK>