[syzbot] [mm?] INFO: rcu detected stall in sys_execve (6)

[syzbot] [mm?] INFO: rcu detected stall in sys_execve (6)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    46ae4d0a4897 Merge git://git.kernel.org/pub/scm/linux/kern..
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=106a549f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3e10d80c64e440c0
dashboard link: https://syzkaller.appspot.com/bug?extid=8bb3e2bee8a429cc76dd
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=144e27c7980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c16ef5753326/disk-46ae4d0a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4a3a038d0ccf/vmlinux-46ae4d0a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/244ada956332/bzImage-46ae4d0a.xz

The issue was bisected to:

commit 5a781ccbd19e4664babcbe4b4ead7aa2b9283d22
Author: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Date:   Sat Sep 29 00:59:43 2018 +0000

    tc: Add support for configuring the taprio scheduler

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=10311900580000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=12311900580000
console output: https://syzkaller.appspot.com/x/log.txt?x=14311900580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8bb3e2bee8a429cc76dd@syzkaller.appspotmail.com
Fixes: 5a781ccbd19e ("tc: Add support for configuring the taprio scheduler")

rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-...D } 2685 jiffies s: 3289 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5444 Comm: syz-executor Not tainted 6.11.0-rc7-syzkaller-01396-g46ae4d0a4897 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:taprio_set_budgets+0x116/0x370 net/sched/sch_taprio.c:666
Code: 44 24 10 4c 89 74 24 18 4d 89 f5 45 31 ff 48 89 5c 24 08 bf 10 00 00 00 4c 89 fe e8 74 8f d2 f7 49 83 ff 0f 0f 87 63 01 00 00 <4c> 89 e8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74
RSP: 0018:ffffc90000007c30 EFLAGS: 00000093
RAX: 0000000000010000 RBX: ffff888028fdb130 RCX: ffff888030aada00
RDX: 0000000000010000 RSI: 0000000000000001 RDI: 0000000000000010
RBP: 0000000000000000 R08: ffffffff89c1021c R09: 1ffff110051cea10
R10: dffffc0000000000 R11: ffffed10051cea11 R12: 0000000000000004
R13: ffff888028e75008 R14: ffff888028e75000 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b8800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb58963cff8 CR3: 00000000311f6000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 advance_sched+0x98d/0xca0 net/sched/sch_taprio.c:977
 __run_hrtimer kernel/time/hrtimer.c:1689 [inline]
 __hrtimer_run_queues+0x59b/0xd50 kernel/time/hrtimer.c:1753
 hrtimer_interrupt+0x396/0x990 kernel/time/hrtimer.c:1815
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline]
 __sysvec_apic_timer_interrupt+0x110/0x3f0 arch/x86/kernel/apic/apic.c:1049
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1043
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x9/0x2a00 arch/x86/kernel/unwind_orc.c:469
Code: 4c 89 f7 e8 69 ad b9 00 e9 53 ff ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 41 57 41 56 <41> 55 41 54 53 48 81 ec a0 00 00 00 48 89 fd 49 bd 00 00 00 00 00
RSP: 0018:ffffc9000422f120 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffffff820edaf2 RCX: ffff888030aada00
RDX: dffffc0000000000 RSI: ffffffff820edaf2 RDI: ffffc9000422f140
RBP: ffffc9000422f1d0 R08: 000000000000000a R09: ffffc9000422f230
R10: 0000000000000003 R11: ffffffff817f2f80 R12: ffff888030aada00
R13: ffffffff817f2f80 R14: ffffc9000422f220 R15: ffffc9000422f140
 arch_stack_walk+0x151/0x1b0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
 kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541
 __call_rcu_common kernel/rcu/tree.c:3106 [inline]
 call_rcu+0x167/0xa70 kernel/rcu/tree.c:3210
 remove_vma mm/mmap.c:189 [inline]
 remove_mt mm/mmap.c:2415 [inline]
 do_vmi_align_munmap+0x155c/0x18c0 mm/mmap.c:2758
 do_vmi_munmap+0x261/0x2f0 mm/mmap.c:2830
 __vm_munmap+0x1fc/0x400 mm/mmap.c:3109
 elf_map fs/binfmt_elf.c:383 [inline]
 elf_load+0x2d8/0x6f0 fs/binfmt_elf.c:408
 load_elf_binary+0xeba/0x2680 fs/binfmt_elf.c:1141
 search_binary_handler fs/exec.c:1827 [inline]
 exec_binprm fs/exec.c:1869 [inline]
 bprm_execve+0xaf8/0x1770 fs/exec.c:1920
 do_execveat_common+0x55f/0x6f0 fs/exec.c:2027
 do_execve fs/exec.c:2101 [inline]
 __do_sys_execve fs/exec.c:2177 [inline]
 __se_sys_execve fs/exec.c:2172 [inline]
 __x64_sys_execve+0x92/0xb0 fs/exec.c:2172
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb5887b0df7
Code: Unable to access opcode bytes at 0x7fb5887b0dcd.
RSP: 002b:00007fb58963ce78 EFLAGS: 00000246 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 00007fb588815ef0 RCX: 00007fb5887b0df7
RDX: 00007ffedbc5b9b0 RSI: 00007ffedbc5bbf0 RDI: 00007ffedbc5cef5
RBP: 00007ffedbc5ba20 R08: 00007fb58963cf20 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000246 R12: 000055558020fa80
R13: 0000000000000100 R14: 00007ffedbc5b9d0 R15: 00007ffedbc5b780
 </TASK>


---
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If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
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If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

Re: [syzbot] [mm?] INFO: rcu detected stall in sys_execve (6)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    a74c7a58ca2c net: freescale: ucc_geth: Return early when T..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=16fdf39a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=323fe5bdde2384a5
dashboard link: https://syzkaller.appspot.com/bug?extid=8bb3e2bee8a429cc76dd
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13d8639a580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=154863fa580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/50a3e60a3908/disk-a74c7a58.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ee6a6a2a52e4/vmlinux-a74c7a58.xz
kernel image: https://storage.googleapis.com/syzbot-assets/033a07d12b3e/bzImage-a74c7a58.xz

The issue was bisected to:

commit 5a781ccbd19e4664babcbe4b4ead7aa2b9283d22
Author: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Date:   Sat Sep 29 00:59:43 2018 +0000

    tc: Add support for configuring the taprio scheduler

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=10311900580000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=12311900580000
console output: https://syzkaller.appspot.com/x/log.txt?x=14311900580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8bb3e2bee8a429cc76dd@syzkaller.appspotmail.com
Fixes: 5a781ccbd19e ("tc: Add support for configuring the taprio scheduler")

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=b674/1/0x4000000000000000 softirq=16193/16205 fqs=2
rcu: 	(detected by 0, t=10502 jiffies, g=13757, q=3905 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6128 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x3a/0xb0 kernel/rcu/tree.c:751
Code: e8 bb 0d b3 09 89 c3 83 f8 08 73 65 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd d0 0d 9b 8d 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 8c 1d 80 00 48 c7 c3 d8 56 81 92 49 03 1e 48 89
RSP: 0018:ffffc90000a08c70 EFLAGS: 00000046
RAX: 1ffffffff1b361bb RBX: 0000000000000001 RCX: 0000000000010002
RDX: 0000000000000000 RSI: ffffffff8bc086c0 RDI: ffffffff8bc08680
RBP: ffffffff81ae6da2 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f045cf R12: 0000000000000000
R13: ffff8880b8728258 R14: ffffffff8d9b0dd8 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888125f1e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9426807ff8 CR3: 0000000077a18000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0x5f/0x340 kernel/locking/lockdep.c:5831
 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline]
 _raw_spin_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:170
 __run_hrtimer kernel/time/hrtimer.c:1781 [inline]
 __hrtimer_run_queues+0x5e2/0xc30 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:deref_stack_reg+0x3/0x230 arch/x86/kernel/unwind_orc.c:418
Code: e8 12 f8 b2 00 48 8b 4c 24 18 e9 f2 fe ff ff 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 <41> 56 41 55 41 54 53 48 83 ec 20 48 89 54 24 18 49 89 f0 49 89 ff
RSP: 0018:ffffc90002f16e00 EFLAGS: 00000283
RAX: fffffffffffffff0 RBX: ffffffff9025420e RCX: 0000000000000000
RDX: ffffc90002f16f28 RSI: ffffc90002f17ad0 RDI: ffffc90002f16ee8
RBP: dffffc0000000000 R08: ffffc90002f16f47 R09: 0000000000000000
R10: ffffc90002f16f38 R11: fffff520005e2de9 R12: ffffc90002f16f38
R13: 1ffff920005e2ddf R14: ffffc90002f16ee8 R15: 1ffffffff204a842
 unwind_next_frame+0x18cc/0x23d0 arch/x86/kernel/unwind_orc.c:-1
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_noprof+0x37d/0x710 mm/slub.c:5270
 mt_alloc_one lib/maple_tree.c:174 [inline]
 mas_alloc_nodes+0x291/0x350 lib/maple_tree.c:1110
 mas_preallocate+0x2e0/0x670 lib/maple_tree.c:5194
 vma_iter_prealloc mm/vma.h:502 [inline]
 vma_shrink+0x18d/0x510 mm/vma.c:1200
 relocate_vma_down+0x4d4/0x4f0 mm/vma_exec.c:91
 setup_arg_pages+0x5cf/0xa90 fs/exec.c:690
 load_elf_binary+0xba4/0x2740 fs/binfmt_elf.c:1028
 search_binary_handler fs/exec.c:1669 [inline]
 exec_binprm fs/exec.c:1701 [inline]
 bprm_execve+0x92e/0x1400 fs/exec.c:1753
 do_execveat_common+0x510/0x6a0 fs/exec.c:1859
 do_execve fs/exec.c:1933 [inline]
 __do_sys_execve fs/exec.c:2009 [inline]
 __se_sys_execve fs/exec.c:2004 [inline]
 __x64_sys_execve+0x94/0xb0 fs/exec.c:2004
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f94259c2e17
Code: Unable to access opcode bytes at 0x7f94259c2ded.
RSP: 002b:00007f9426807df8 EFLAGS: 00000206 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 00007ffd48e33ef5 RCX: 00007f94259c2e17
RDX: 00007ffd48e32ba0 RSI: 00007ffd48e32de0 RDI: 00007ffd48e33ef5
RBP: 00007f9426807e70 R08: 00007f9426807f20 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000206 R12: 00007ffd48e32de0
R13: 00007ffd48e32ba0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10495 jiffies! g13757 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:27480 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6960
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 5203 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xcc5/0x1260 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 d4 97 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 7f 93 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 63 93
RSP: 0000:ffffc90003057820 EFLAGS: 00000293
RAX: ffffffff81b5654d RBX: 1ffff110170e8129 RCX: ffff88807d153d00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003057950 R08: ffffffff8f822e77 R09: 1ffffffff1f045ce
R10: dffffc0000000000 R11: fffffbfff1f045cf R12: ffff8880b8740948
R13: dffffc0000000000 R14: ffff8880b863bb00 R15: 0000000000000001
FS:  00007f6e0f393880(0000) GS:ffff888125e1e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ec54628550 CR3: 000000007d7b8000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
 flush_tlb_mm_range+0x60a/0x1170 arch/x86/mm/tlb.c:1472
 flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline]
 ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:103
 wp_page_copy mm/memory.c:3785 [inline]
 do_wp_page+0x1bb1/0x5810 mm/memory.c:4180
 handle_pte_fault mm/memory.c:6289 [inline]
 __handle_mm_fault mm/memory.c:6411 [inline]
 handle_mm_fault+0x14c5/0x32b0 mm/memory.c:6580
 do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x71/0xd0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f6e0ecb5dfe
Code: 00 00 66 0f ef c0 41 0f 11 44 24 20 49 89 54 24 10 49 89 74 24 18 4c 89 66 10 4c 89 62 18 48 89 c2 48 83 ca 01 49 89 54 24 08 <49> 89 04 04 48 83 c4 10 5b 41 5c 41 5d c3 0f 1f 40 00 48 89 cf 48
RSP: 002b:00007fff1a84f050 EFLAGS: 00010206
RAX: 0000000000002a20 RBX: 0000000000000740 RCX: 000055ec54627e10
RDX: 0000000000002a21 RSI: 00007f6e0edf1b20 RDI: 000055ec54627e10
RBP: 00007f6e0edf1ac0 R08: 0000000000000740 R09: 0000000000000010
R10: 000055ec24e255e0 R11: 0000000000000004 R12: 000055ec54625b30
R13: 00007f6e0edf1ac0 R14: 0000000000000740 R15: 00007f6e0edf1ac0
 </TASK>


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

Re: [syzbot] [mm?] INFO: rcu detected stall in sys_execve (6)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: rcu detected stall in worker_thread

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...0: (1 ticks this GP) idle=1544/1/0x4000000000000000 softirq=21116/21116 fqs=7
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:        0          0            0
rcu: 	cputime:        0          0            0   ==> 21980(ms)
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6477/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=15529, q=2686 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_power_efficient gc_worker
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline]
RIP: 0010:queued_spin_is_locked include/asm-generic/qspinlock.h:57 [inline]
RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:101 [inline]
RIP: 0010:do_raw_spin_unlock+0x59/0x240 kernel/locking/spinlock_debug.c:141
Code: 84 01 00 00 41 81 3e ad 4e ad de 0f 85 f3 00 00 00 48 89 df be 04 00 00 00 e8 53 8a 88 00 48 89 d8 48 c1 e8 03 42 0f b6 04 20 <84> c0 0f 85 74 01 00 00 83 3b 00 0f 84 ea 00 00 00 4c 8d 73 10 4d
RSP: 0018:ffffc90000007c28 EFLAGS: 00000806
RAX: 0000000000000000 RBX: ffff888030b1e2a8 RCX: ffffffff819e93bd
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff888030b1e2a8
RBP: ffff88805a66a150 R08: ffff888030b1e2ab R09: 1ffff11006163c55
R10: dffffc0000000000 R11: ffffed1006163c56 R12: dffffc0000000000
R13: ffff888030b1e000 R14: ffff888030b1e2ac R15: ffff88805d10fc00
FS:  0000000000000000(0000) GS:ffff888125e1e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffdb6036498 CR3: 000000000dd3a000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __raw_spin_unlock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_unlock+0x1e/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 advance_sched+0x99f/0xc90 net/sched/sch_taprio.c:987
 __run_hrtimer kernel/time/hrtimer.c:1777 [inline]
 __hrtimer_run_queues+0x51c/0xc30 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:seqcount_lockdep_reader_access+0xed/0x100 include/linux/seqlock.h:75
Code: 00 75 11 e8 05 82 3e f8 4d 85 f6 75 16 e8 fb 81 3e f8 eb 15 e8 f4 81 3e f8 e8 5f 7a d7 01 4d 85 f6 74 ea e8 e5 81 3e f8 fb 5b <41> 5e e9 4c 59 da 01 cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90
RSP: 0018:ffffc900000e7910 EFLAGS: 00000293
RAX: ffffffff898276cb RBX: 0000000000000001 RCX: ffff88801c2c8000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900000e7a70 R08: ffffffff8f822e77 R09: 1ffffffff1f045ce
R10: dffffc0000000000 R11: fffffbfff1f045cf R12: ffff8880b863a080
R13: ffff88801be91418 R14: 0000000000000200 R15: 0000000000040000
 nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:342 [inline]
 gc_worker+0x308/0x1380 net/netfilter/nf_conntrack_core.c:1548
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
task:dhcpcd-run-hook state:R  running task     stack:27640 pid:6477  tgid:6477  ppid:6464   task_flags:0x40004c flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7190
 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x222/0x340 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 70 00 bc 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 5a 2f e2 10 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 3f df be 09 cc 48 8d 3d 97 82 e7
RSP: 0018:ffffc900031073f8 EFLAGS: 00000282
RAX: 8aa7093569192b00 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 00000000bfbdb79f RSI: ffffffff8d9774de RDI: ffffffff8bc086e0
RBP: ffffffff8173fdd5 R08: ffffffff8173fdd5 R09: ffffffff8df41aa0
R10: ffffc90003107558 R11: ffffffff81acf4d0 R12: 0000000000000002
R13: ffffffff8df41aa0 R14: 0000000000000000 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2540 [inline]
 slab_free mm/slub.c:6670 [inline]
 kmem_cache_free+0x197/0x620 mm/slub.c:6781
 anon_vma_chain_free mm/rmap.c:146 [inline]
 unlink_anon_vmas+0x2cc/0x670 mm/rmap.c:420
 free_pgtables+0x57f/0x9d0 mm/memory.c:399
 exit_mmap+0x431/0xb10 mm/mmap.c:1288
 __mmput+0x118/0x430 kernel/fork.c:1173
 exit_mm+0x169/0x230 kernel/exit.c:581
 do_exit+0x627/0x22f0 kernel/exit.c:959
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
 __do_sys_exit_group kernel/exit.c:1123 [inline]
 __se_sys_exit_group kernel/exit.c:1121 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1121
 x64_sys_call+0x2210/0x2210 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe808c126c5
RSP: 002b:00007ffdb60363a8 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007ffdb6036604 RCX: 00007fe808c126c5
RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000000
RBP: 0000000000000003 R08: 00007ffdb60364a0 R09: 0000000000000002
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffdb60366e0 R14: 00007fe808e22000 R15: 000055f28d607d98
 </TASK>
rcu: rcu_preempt kthread starved for 2154 jiffies! g15529 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27480 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6960
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xcc5/0x1260 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 d4 97 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 7f 93 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 63 93
RSP: 0018:ffffc90000126540 EFLAGS: 00000293
RAX: ffffffff81b5654d RBX: 1ffff110170c856d RCX: ffff88801c2f0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000126670 R08: ffff888076e16d87 R09: 1ffff1100edc2db0
R10: dffffc0000000000 R11: ffffffff8175f0c0 R12: ffff8880b8642b68
R13: dffffc0000000000 R14: ffff8880b873bb00 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125f1e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8357b4de9c CR3: 0000000075acc000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
 flush_tlb_mm_range+0x60a/0x1170 arch/x86/mm/tlb.c:1472
 flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline]
 ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:103
 page_vma_mkclean_one+0x401/0x790 mm/rmap.c:1017
 page_mkclean_one+0x1c0/0x280 mm/rmap.c:1065
 __rmap_walk_file+0x467/0x620 mm/rmap.c:2927
 rmap_walk mm/rmap.c:2971 [inline]
 folio_mkclean+0x297/0x390 mm/rmap.c:1097
 folio_clear_dirty_for_io+0x1a5/0x710 mm/page-writeback.c:2932
 mpage_submit_folio+0x86/0x2b0 fs/ext4/inode.c:2068
 mpage_map_and_submit_buffers fs/ext4/inode.c:2330 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2520 [inline]
 ext4_do_writepages+0x1fe9/0x4500 fs/ext4/inode.c:2932
 ext4_writepages+0x203/0x350 fs/ext4/inode.c:3026
 do_writepages+0x32e/0x550 mm/page-writeback.c:2598
 __writeback_single_inode+0x133/0x1240 fs/fs-writeback.c:1737
 writeback_sb_inodes+0x93a/0x1870 fs/fs-writeback.c:2030
 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2107
 wb_writeback+0x43f/0xaa0 fs/fs-writeback.c:2218
 wb_check_old_data_flush fs/fs-writeback.c:2322 [inline]
 wb_do_writeback fs/fs-writeback.c:2375 [inline]
 wb_workfn+0xad2/0xed0 fs/fs-writeback.c:2403
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>


Tested on:

commit:         f40ddcc0 Revert "nfc/nci: Add the inconsistency check ..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=105ff522580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=323fe5bdde2384a5
dashboard link: https://syzkaller.appspot.com/bug?extid=8bb3e2bee8a429cc76dd
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1077f522580000

Re: [syzbot] [mm?] INFO: rcu detected stall in sys_execve (6)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: workqueue lockup

BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=-20 stuck for 141s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x100
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=6 refcnt=7
    pending: 3*nsim_dev_hwstats_traffic_work, psi_avgs_work, vmstat_shepherd, ovs_dp_masks_rebalance
  pwq 6: cpus=1 node=0 flags=0x2 nice=0 active=4 refcnt=5
    in-flight: 5940:nsim_fib_event_work nsim_fib_event_work ,39:nsim_fib_event_work nsim_fib_event_work
workqueue events_long: flags=0x100
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=4 refcnt=5
    pending: 4*defense_work_handler
workqueue events_unbound: flags=0x2
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=2 refcnt=3
    in-flight: 3887:toggle_allocation_gate
    pending: flush_memcg_stats_dwork
workqueue events_unbound: flags=0x2
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=8 refcnt=9
    in-flight: 60:cfg80211_wiphy_work ,3910:nsim_dev_trap_report_work ,1136:nsim_dev_trap_report_work ,4325:nsim_dev_trap_report_work ,3517:cfg80211_wiphy_work ,1101:nsim_dev_trap_report_work ,3469:crng_reseed
    pending: nsim_dev_trap_report_work
workqueue events_freezable: flags=0x104
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: update_balloon_stats_func
workqueue events_power_efficient: flags=0x180
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=8 refcnt=9
    in-flight: 794:reg_check_chans_work
    pending: neigh_managed_work, neigh_periodic_work, 2*check_lifetime, do_cache_clean, 2*check_lifetime
  pwq 6: cpus=1 node=0 flags=0x2 nice=0 active=2 refcnt=3
    in-flight: 5865:neigh_periodic_work ,24:gc_worker
workqueue kvfree_rcu_reclaim: flags=0xa
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=2 refcnt=3
    in-flight: 1013:kfree_rcu_monitor
    pending: kfree_rcu_monitor
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    in-flight: 1141:kfree_rcu_monitor
workqueue mm_percpu_wq: flags=0x8
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    pending: vmstat_update
workqueue writeback: flags=0x4a
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    in-flight: 4346:wb_workfn
workqueue kblockd: flags=0x18
  pwq 3: cpus=0 node=0 flags=0x0 nice=-20 active=1 refcnt=2
    pending: blk_mq_run_work_fn
  pwq 7: cpus=1 node=0 flags=0x0 nice=-20 active=2 refcnt=3
    pending: blk_mq_timeout_work, blk_mq_requeue_work
workqueue ipv6_addrconf: flags=0x6000a
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=231
    in-flight: 340:addrconf_dad_work
    inactive: 221*addrconf_dad_work, addrconf_verify_work, addrconf_dad_work, 4*addrconf_verify_work
workqueue krxrpcd: flags=0x2001a
  pwq 9: cpus=0-1 node=0 flags=0x4 nice=-20 active=1 refcnt=9
    pending: rxrpc_peer_keepalive_worker
    inactive: 5*rxrpc_peer_keepalive_worker
workqueue bat_events: flags=0x6000a
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=40
    pending: batadv_mcast_mla_update
    inactive: 4*batadv_mcast_mla_update, 7*batadv_iv_send_outstanding_bat_ogm_packet, 5*batadv_purge_orig, 5*batadv_iv_send_outstanding_bat_ogm_packet, 5*batadv_tt_purge, batadv_dat_purge, 2*batadv_bla_periodic_work, batadv_dat_purge, batadv_bla_periodic_work, batadv_dat_purge, batadv_bla_periodic_work, batadv_dat_purge, batadv_bla_periodic_work, batadv_dat_purge
workqueue hci0: flags=0x20012
  pwq 9: cpus=0-1 node=0 flags=0x4 nice=-20 active=1 refcnt=4
    pending: hci_conn_timeout
workqueue hci2: flags=0x20012
  pwq 9: cpus=0-1 node=0 flags=0x4 nice=-20 active=1 refcnt=4
    pending: hci_conn_timeout
workqueue wg-kex-wg0: flags=0x124
  pwq 6: cpus=1 node=0 flags=0x2 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_receive_worker
workqueue wg-kex-wg0: flags=0x6
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_send_worker
workqueue wg-crypt-wg0: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x2 nice=0 active=1 refcnt=2
    pending: wg_packet_encrypt_worker
workqueue wg-crypt-wg1: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=1 refcnt=2
    in-flight: 9:wg_packet_tx_worker
workqueue wg-kex-wg2: flags=0x6
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=1 refcnt=2
    pending: wg_packet_handshake_send_worker
workqueue wg-crypt-wg2: flags=0x128
  pwq 2: cpus=0 node=0 flags=0x0 nice=0 active=2 refcnt=3
    in-flight: 5963:wg_packet_tx_worker
    pending: wg_packet_encrypt_worker
  pwq 6: cpus=1 node=0 flags=0x2 nice=0 active=5 refcnt=6
    in-flight: 6465:wg_packet_encrypt_worker wg_packet_encrypt_worker ,5964:wg_packet_tx_worker wg_packet_tx_worker
    pending: wg_packet_decrypt_worker
workqueue wg-kex-wg0: flags=0x6
  pwq 8: cpus=0-1 flags=0x6 nice=0 active=3 refcnt=4
    in-flight: 1045:wg_packet_handshake_send_worker ,13:wg_packet_handshake_send_worker wg_packet_handshake_send_worker
workqueue wg-crypt-wg1: flags=0x128
  pwq 6: cpus=1 node=0 flags=0x2 nice=0 active=2 refcnt=3
    pending: wg_packet_tx_worker, wg_packet_encrypt_worker
pool 2: cpus=0 node=0 flags=0x0 nice=0 hung=64s workers=6 idle: 5889 5941 10
pool 6: cpus=1 node=0 flags=0x2 nice=0 hung=65s workers=7 manager: 128
pool 8: cpus=0-1 flags=0x6 nice=0 hung=65s workers=18 manager: 36 idle: 12 1341 50
Showing backtraces of running workers in stalled CPU-bound worker pools:


Tested on:

commit:         f40ddcc0 Revert "nfc/nci: Add the inconsistency check ..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=15a7db9a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=323fe5bdde2384a5
dashboard link: https://syzkaller.appspot.com/bug?extid=8bb3e2bee8a429cc76dd
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=143ff522580000

Re: [syzbot] [mm?] INFO: rcu detected stall in sys_execve (6)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: rcu detected stall in corrupted

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6251/3:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=16273, q=1513 ncpus=2)
task:udevd           state:R  running task     stack:25432 pid:6251  tgid:6251  ppid:5199   task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7047
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 filemap_map_pages+0x192d/0x1fd0 mm/filemap.c:3931
 do_fault_around mm/memory.c:5713 [inline]
 do_read_fault mm/memory.c:5746 [inline]
 do_fault mm/memory.c:5889 [inline]
 do_pte_missing+0x20b0/0x3330 mm/memory.c:4401
 handle_pte_fault mm/memory.c:6273 [inline]
 __handle_mm_fault mm/memory.c:6411 [inline]
 handle_mm_fault+0x1b26/0x32b0 mm/memory.c:6580
 do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x71/0xd0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7fdbcbf6be80
RSP: 002b:00007ffc0ad89938 EFLAGS: 00010246
RAX: 0000000000000006 RBX: 00005588ef53c568 RCX: 0000000000000019
RDX: 0000000000000191 RSI: 00007fdbcb9f1ca0 RDI: 00005589070c4e70
RBP: 00005589070a7910 R08: 0000000002000000 R09: 0000000000000003
R10: 0000000000000000 R11: 0000000000000297 R12: 00005588ef53c588
R13: 00007ffc0ad899b0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 7525 jiffies! g16273 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:28008 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6960
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 6318 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xcce/0x1260 kernel/smp.c:877
Code: 01 31 ff e8 d4 97 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 7f 93 0b 00 eb 38 f3 90 42 0f b6 04 2b 84 c0 75 11 <41> f7 04 24 01 00 00 00 74 1e e8 63 93 0b 00 eb e4 44 89 e1 80 e1
RSP: 0000:ffffc90003d0f820 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 1ffff110170e8129 RCX: ffff888026fc3d00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003d0f950 R08: ffffffff8f822e77 R09: 1ffffffff1f045ce
R10: dffffc0000000000 R11: fffffbfff1f045cf R12: ffff8880b8740948
R13: dffffc0000000000 R14: ffff8880b863bb00 R15: 0000000000000001
FS:  00007fdbcbf47880(0000) GS:ffff888125e1e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005589070d6f28 CR3: 0000000076b96000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
 flush_tlb_mm_range+0x60a/0x1170 arch/x86/mm/tlb.c:1472
 flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline]
 ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:103
 wp_page_copy mm/memory.c:3785 [inline]
 do_wp_page+0x1bb1/0x5810 mm/memory.c:4180
 handle_pte_fault mm/memory.c:6289 [inline]
 __handle_mm_fault mm/memory.c:6411 [inline]
 handle_mm_fault+0x14c5/0x32b0 mm/memory.c:6580
 do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x71/0xd0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7fdbcb8b5b69
Code: 10 48 81 f9 ff 03 00 00 76 28 48 8b 57 20 48 85 d2 74 1f 48 3b 7a 28 75 76 48 8b 4f 28 48 3b 79 20 75 6c 48 83 78 20 00 74 17 <48> 89 4a 28 48 89 51 20 48 83 c4 08 c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc0ad89870 EFLAGS: 00010202
RAX: 00007fdbcb9f2070 RBX: 00000000000009b0 RCX: 00005589070d6f00
RDX: 00005589070d6f00 RSI: 00007fdbcb9f2070 RDI: 00005589070d6f00
RBP: 00007fdbcb9f1ac0 R08: 00000000000009b0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00005589070d47a0
R13: 00007fdbcb9f1ac0 R14: 00000000000009b0 R15: 00007fdbcb9f1ac0
 </TASK>


Tested on:

commit:         f40ddcc0 Revert "nfc/nci: Add the inconsistency check ..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=160153fa580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=323fe5bdde2384a5
dashboard link: https://syzkaller.appspot.com/bug?extid=8bb3e2bee8a429cc76dd
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=118fa852580000

Re: [syzbot] [mm?] INFO: rcu detected stall in sys_execve (6)

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: rcu detected stall in worker_thread

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=3fa4/1/0x4000000000000000 softirq=23801/23814 fqs=1
rcu: 	(detected by 0, t=10503 jiffies, g=17209, q=7435 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5941 Comm: kworker/1:5 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_power_efficient gc_worker
RIP: 0010:check_region_inline mm/kasan/generic.c:185 [inline]
RIP: 0010:kasan_check_range+0x19/0x2c0 mm/kasan/generic.c:200
Code: cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 55 41 57 41 56 41 55 41 54 53 b0 01 48 85 f6 0f 84 ba 01 00 00 <4c> 8d 04 37 49 39 f8 0f 82 82 02 00 00 49 b9 00 00 00 00 00 80 ff
RSP: 0018:ffffc90000a08ba8 EFLAGS: 00000002
RAX: 00000000ffffff01 RBX: ffffffff99b74750 RCX: ffffffff819e9061
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000a08c20
RBP: ffffc90000a08c98 R08: ffffffff99b74753 R09: 1ffffffff336e8ea
R10: dffffc0000000000 R11: fffffbfff336e8eb R12: ffffffff99b74760
R13: ffffffff99b74758 R14: 1ffffffff336e8ec R15: 1ffffffff336e8eb
FS:  0000000000000000(0000) GS:ffff888125f1e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff7a7c27432 CR3: 0000000073668000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 instrument_read_write include/linux/instrumented.h:54 [inline]
 atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1301 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:111 [inline]
 do_raw_spin_lock+0x121/0x290 kernel/locking/spinlock_debug.c:116
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
 _raw_spin_lock_irqsave+0x4c/0x60 kernel/locking/spinlock.c:162
 debug_object_deactivate+0x6d/0x360 lib/debugobjects.c:873
 debug_hrtimer_deactivate kernel/time/hrtimer.c:443 [inline]
 debug_deactivate+0x1d/0x1e0 kernel/time/hrtimer.c:483
 __run_hrtimer kernel/time/hrtimer.c:1745 [inline]
 __hrtimer_run_queues+0x2b0/0xc30 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:-1 [inline]
RIP: 0010:rcu_is_watching+0x44/0xb0 kernel/rcu/tree.c:751
Code: 73 65 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd d0 0d 9b 8d 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 8c 1d 80 00 <48> c7 c3 d8 56 81 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38
RSP: 0018:ffffc90003d77860 EFLAGS: 00000246
RAX: 1ffffffff1b361bb RBX: 0000000000000001 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff8bc086c0 RDI: ffffffff8bc08680
RBP: ffffffff8983265b R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f045cf R12: 0000000000000002
R13: ffffffff8df41aa0 R14: ffffffff8d9b0dd8 R15: dffffc0000000000
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0x5f/0x340 kernel/locking/lockdep.c:5831
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 gc_worker+0x28c/0x13d0 net/netfilter/nf_conntrack_core.c:1546
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: rcu_preempt kthread starved for 10479 jiffies! g17209 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:27416 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6960
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 6390 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xcce/0x1260 kernel/smp.c:877
Code: 01 31 ff e8 d4 97 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 7f 93 0b 00 eb 38 f3 90 42 0f b6 04 2b 84 c0 75 11 <41> f7 04 24 01 00 00 00 74 1e e8 63 93 0b 00 eb e4 44 89 e1 80 e1
RSP: 0018:ffffc900031374a0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 1ffff110170e8129 RCX: ffff8880254c9e80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900031375e0 R08: ffffffff8f822e77 R09: 1ffffffff1f045ce
R10: dffffc0000000000 R11: fffffbfff1f045cf R12: ffff8880b8740948
R13: dffffc0000000000 R14: ffff8880b863bb00 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888125e1e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055fad049c6d8 CR3: 000000000dd3a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
 flush_tlb_mm_range+0x60a/0x1170 arch/x86/mm/tlb.c:1472
 tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
 tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline]
 tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403
 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497
 free_ldt_pgtables+0x17b/0x320 arch/x86/kernel/ldt.c:411
 arch_exit_mmap arch/x86/include/asm/mmu_context.h:234 [inline]
 exit_mmap+0x174/0xb10 mm/mmap.c:1263
 __mmput+0x118/0x430 kernel/fork.c:1173
 exit_mm+0x169/0x230 kernel/exit.c:581
 do_exit+0x627/0x22f0 kernel/exit.c:959
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
 get_signal+0x1285/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f175fd915dc
Code: Unable to access opcode bytes at 0x7f175fd915b2.
RSP: 002b:00007ffd6bb31250 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: 0000000000000040 RBX: 00007f1760b14620 RCX: 00007f175fd915dc
RDX: 0000000000000040 RSI: 00007f1760b14670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffd6bb312a4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f1760b14670 R15: 0000000000000000
 </TASK>


Tested on:

commit:         f40ddcc0 Revert "nfc/nci: Add the inconsistency check ..
git tree:       net
console output: https://syzkaller.appspot.com/x/log.txt?x=16b06852580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=323fe5bdde2384a5
dashboard link: https://syzkaller.appspot.com/bug?extid=8bb3e2bee8a429cc76dd
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1688eb9a580000

Re: [syzbot] [mm?] INFO: rcu detected stall in sys_execve (6)

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file net/netfilter/nf_conntrack_core.c
Hunk #1 FAILED at 1517.
patch: **** unexpected end of file in patch



Tested on:

commit:         f40ddcc0 Revert "nfc/nci: Add the inconsistency check ..
git tree:       net
kernel config:  https://syzkaller.appspot.com/x/.config?x=323fe5bdde2384a5
dashboard link: https://syzkaller.appspot.com/bug?extid=8bb3e2bee8a429cc76dd
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=15706852580000