BUG: soft lockup in wb

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
linux-6.1	BUG: soft lockup in wb_workfn origin:upstream	1	C		error	5	162d	416d	0/3	upstream: reported C repro on 2024/10/24 21:18
linux-5.15	INFO: rcu detected stall in wb_workfn origin:lts-only	1	syz		error	4	431d	503d	0/3	auto-obsoleted due to no activity on 2025/01/21 00:06
upstream	INFO: rcu detected stall in wb_workfn (4) mm	1	C	error		45	1d17h	156d	0/29	upstream: reported C repro on 2025/07/11 13:28
linux-5.15	INFO: rcu detected stall in wb_workfn (2) origin:lts-only	1	C		error	44	2d16h	304d	0/3	upstream: reported C repro on 2025/02/13 22:15

watchdog: BUG: soft lockup - CPU#0 stuck for 123s! [kworker/u4:6:11680] Modules linked in: irq event stamp: 0 hardirqs last enabled at (0): [<0000000000000000>] 0x0 hardirqs last disabled at (0): [<ffffffff81436c35>] copy_process+0x1815/0x6b00 kernel/fork.c:1960 softirqs last enabled at (0): [<ffffffff81436cdc>] copy_process+0x18bc/0x6b00 kernel/fork.c:1963 softirqs last disabled at (0): [<0000000000000000>] 0x0 CPU: 0 PID: 11680 Comm: kworker/u4:6 Not tainted 5.3.0-rc4 #126 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-8:0) RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline] RIP: 0010:csd_lock_wait kernel/smp.c:109 [inline] RIP: 0010:smp_call_function_single+0x188/0x480 kernel/smp.c:311 Code: 00 e8 dc 03 0b 00 48 8b 4c 24 08 48 8b 54 24 10 48 8d 74 24 40 8b 7c 24 1c e8 b4 f7 ff ff 41 89 c5 eb 07 e8 ba 03 0b 00 f3 90 <44> 8b 64 24 58 31 ff 41 83 e4 01 44 89 e6 e8 25 05 0b 00 45 85 e4 RSP: 0018:ffff88805c936c80 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffff88805c93e480 RBX: 1ffff1100b926d94 RCX: ffffffff81676e6b RDX: 0000000000000000 RSI: ffffffff81676e56 RDI: 0000000000000005 RBP: ffff88805c936d50 R08: ffff88805c93e480 R09: ffffed1015d26cc1 R10: ffffed1015d26cc0 R11: ffff8880ae936607 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000758090 CR3: 00000000a1ffb000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: smp_call_function_many+0x7ba/0x940 kernel/smp.c:451 on_each_cpu_mask+0x4d/0x280 kernel/smp.c:645 on_each_cpu_cond_mask+0x17e/0x220 kernel/smp.c:697 native_flush_tlb_others+0x220/0x4f0 arch/x86/mm/tlb.c:710 flush_tlb_others arch/x86/include/asm/paravirt.h:68 [inline] flush_tlb_mm_range+0x299/0x4e0 arch/x86/mm/tlb.c:798 flush_tlb_page arch/x86/include/asm/tlbflush.h:569 [inline] ptep_clear_flush+0x141/0x170 mm/pgtable-generic.c:88 page_mkclean_one+0x371/0x6b0 mm/rmap.c:918 rmap_walk_file+0x585/0xcf0 mm/rmap.c:1887 rmap_walk+0x130/0x1c0 mm/rmap.c:1905 page_mkclean+0x269/0x340 mm/rmap.c:987 clear_page_dirty_for_io+0x35f/0xde0 mm/page-writeback.c:2686 mpage_submit_page+0x8d/0x270 fs/ext4/inode.c:2234 mpage_process_page_bufs+0x60c/0x720 fs/ext4/inode.c:2364 mpage_prepare_extent_to_map+0xa05/0xf90 fs/ext4/inode.c:2722 ext4_writepages+0x998/0x2ec0 fs/ext4/inode.c:2850 do_writepages+0xfa/0x2a0 mm/page-writeback.c:2342 __writeback_single_inode+0x136/0x13f0 fs/fs-writeback.c:1364 writeback_sb_inodes+0x596/0xf20 fs/fs-writeback.c:1628 wb_writeback+0x2a5/0xd90 fs/fs-writeback.c:1804 ? 0xffffffff81000000 wb_do_writeback fs/fs-writeback.c:1949 [inline] wb_workfn+0x343/0x1230 fs/fs-writeback.c:1990 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 2096 Comm: syz-executor.1 Not tainted 5.3.0-rc4 #126 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_memory_region+0x21/0x1a0 mm/kasan/generic.c:191 Code: 2e 0f 1f 84 00 00 00 00 00 48 85 f6 0f 84 34 01 00 00 48 b8 ff ff ff ff ff 7f ff ff 55 0f b6 d2 48 39 c7 48 89 e5 41 55 41 54 <53> 0f 86 07 01 00 00 4c 8d 5c 37 ff 49 89 f8 48 b8 00 00 00 00 00 RSP: 0018:ffff88805acff570 EFLAGS: 00000216 RAX: ffff7fffffffffff RBX: ffff888098d53580 RCX: ffffffff815959a7 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff888098d53580 RBP: ffff88805acff580 R08: 1ffff110131aa6b0 R09: ffffed10131aa6b1 R10: ffffed10131aa6b0 R11: ffff888098d53583 R12: 0000000000000001 R13: 0000000000000003 R14: ffffed10131aa6b0 R15: 0000000000000001 FS: 00007fe0e4868700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000093e21000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __kasan_check_read+0x11/0x20 mm/kasan/common.c:92 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] virt_spin_lock arch/x86/include/asm/qspinlock.h:83 [inline] native_queued_spin_lock_slowpath+0xb7/0x9f0 kernel/locking/qspinlock.c:325 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:654 [inline] queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:50 [inline] queued_spin_lock include/asm-generic/qspinlock.h:81 [inline] do_raw_spin_lock+0x20e/0x2e0 kernel/locking/spinlock_debug.c:113 __raw_spin_lock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_lock+0x37/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] zap_pte_range mm/memory.c:1020 [inline] zap_pmd_range mm/memory.c:1161 [inline] zap_pud_range mm/memory.c:1190 [inline] zap_p4d_range mm/memory.c:1211 [inline] unmap_page_range+0x82c/0x2170 mm/memory.c:1232 unmap_single_vma+0x19d/0x300 mm/memory.c:1277 unmap_vmas+0x135/0x280 mm/memory.c:1309 exit_mmap+0x2ba/0x530 mm/mmap.c:3145 __mmput kernel/fork.c:1064 [inline] mmput+0x179/0x4d0 kernel/fork.c:1085 exit_mm kernel/exit.c:547 [inline] do_exit+0x84e/0x2e50 kernel/exit.c:866 do_group_exit+0x135/0x360 kernel/exit.c:983 get_signal+0x47c/0x2500 kernel/signal.c:2729 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:159 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459829 Code: Bad RIP value. RSP: 002b:00007fe0e4867cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000075c078 RCX: 0000000000459829 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000075c078 RBP: 000000000075c070 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075c07c R13: 0000000000a6fb7f R14: 00007fe0e48689c0 R15: 000000000075c07c