syzbot


INFO: task hung in vfs_coredump (2)

Status: upstream: reported C repro on 2025/08/03 18:20
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+6ed94e81a1492fe1d512@syzkaller.appspotmail.com
First crash: 54d, last: 1d21h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kernel?] INFO: task hung in vfs_coredump (2) 0 (1) 2025/08/03 18:20
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in vfs_coredump io-uring 1 syz 3 82d 79d 0/29 closed as invalid on 2025/07/10 23:03

Sample crash report:
INFO: task syz.0.17:6083 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:26344 pid:6083  tgid:6083  ppid:5991   task_flags:0x400640 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5360 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964
 __schedule_loop kernel/sched/core.c:7046 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7061
 schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common+0x3da/0x710 kernel/sched/completion.c:121
 wait_for_common kernel/sched/completion.c:132 [inline]
 wait_for_completion_state+0x1c/0x40 kernel/sched/completion.c:269
 coredump_wait fs/coredump.c:534 [inline]
 vfs_coredump+0x8cf/0x2a60 fs/coredump.c:1131
 get_signal+0x1109/0x1340 kernel/signal.c:3019
 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:40 [inline]
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 irqentry_exit_to_user_mode+0x81/0x120 kernel/entry/common.c:73
 exc_page_fault+0xab/0x100 arch/x86/mm/fault.c:1535
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f73b6c4f927
RSP: 002b:00007ffd385e63e0 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 000000000000000b RCX: ffffffffffffffa8
RDX: 00007ffd385e6400 RSI: 00007ffd385e6530 RDI: 000000000000000b
RBP: 0000000000000032 R08: 7fffffffffffffff R09: 00000007386e4dbf
R10: 00007ffd386e4bc0 R11: 0000000000000246 R12: 00007f73b6fd609c
R13: 00007ffd386e4bc0 R14: 000000000001a29f R15: 00007ffd386e4be0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e53c820 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e53c820 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e53c820 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5631:
 #0: ffff88814dfaf0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900036c62f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
6 locks held by syz-executor/6362:

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:332 [inline]
 watchdog+0xf60/0xfa0 kernel/hung_task.c:495
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 3487 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:406 [inline]
RIP: 0010:unwind_next_frame+0xc3c/0x2390 arch/x86/kernel/unwind_orc.c:585
Code: 3c 01 0f 85 f9 0c 00 00 48 8d 43 08 4c 39 f8 0f 97 c1 4c 39 e0 0f 96 c0 20 c8 3c 01 0f 85 df 0c 00 00 48 89 df e8 84 23 00 00 <48> 89 c3 48 bd 00 00 00 00 00 fc ff df 48 8b 44 24 30 80 3c 28 00
RSP: 0018:ffffc9000b8c6918 EFLAGS: 00000202
RAX: ffffffff8b007ecf RBX: ffffc9000b8c7988 RCX: 1ffff92001718d01
RDX: ffffffff9116c31a RSI: 0000000000000002 RDI: ffffc9000b8c7988
RBP: 1ffff92001718d3e R08: 0000000000000001 R09: ffffffff81740d25
R10: ffffc9000b8c6a38 R11: ffffffff81ac8160 R12: ffffc9000b8c8000
R13: 1ffff92001718d3f R14: ffffc9000b8c69e8 R15: ffffc9000b8c0000
FS:  0000000000000000(0000) GS:ffff8881258a7000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fca32d07d60 CR3: 000000000e338000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 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:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587
 kasan_save_free_info mm/kasan/kasan.h:406 [inline]
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2474 [inline]
 slab_free mm/slub.c:6181 [inline]
 kfree+0x199/0x6d0 mm/slub.c:6389
 ieee80211_inform_bss+0xbd9/0x10a0 net/mac80211/scan.c:160
 rdev_inform_bss net/wireless/rdev-ops.h:418 [inline]
 cfg80211_inform_single_bss_data+0xd05/0x1ac0 net/wireless/scan.c:2385
 cfg80211_inform_bss_data+0x1fb/0x3b30 net/wireless/scan.c:3240
 cfg80211_inform_bss_frame_data+0x3d7/0x730 net/wireless/scan.c:3331
 ieee80211_bss_info_update+0x746/0x9e0 net/mac80211/scan.c:226
 ieee80211_rx_bss_info net/mac80211/ibss.c:1094 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1573 [inline]
 ieee80211_ibss_rx_queued_mgmt+0xa36/0x2ae0 net/mac80211/ibss.c:1600
 ieee80211_iface_process_skb net/mac80211/iface.c:1699 [inline]
 ieee80211_iface_work+0x85f/0x12d0 net/mac80211/iface.c:1753
 cfg80211_wiphy_work+0x2bb/0x470 net/wireless/core.c:435
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (25):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/16 04:36 linux-next 590b221ed425 e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in vfs_coredump
2025/09/11 05:15 linux-next 5f540c4aade9 fdeaa69b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in vfs_coredump
2025/09/06 15:51 linux-next be5d4872e528 d291dd2d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in vfs_coredump
2025/07/30 18:01 linux-next d086c886ceb9 f8f2b4da .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in vfs_coredump
2025/09/17 05:34 upstream 5aca7966d2a7 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in vfs_coredump
2025/09/13 11:25 upstream 22f20375f5b7 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in vfs_coredump
2025/09/07 03:00 upstream b236920731dd d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in vfs_coredump
2025/09/02 08:19 upstream b320789d6883 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in vfs_coredump
2025/08/25 11:57 upstream 69fd6b99b8f8 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in vfs_coredump
2025/08/24 08:36 upstream 8d245acc1e88 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in vfs_coredump
2025/08/24 02:47 upstream 8d245acc1e88 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in vfs_coredump
2025/08/23 12:52 upstream 6debb6904172 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in vfs_coredump
2025/08/22 14:35 upstream 3957a5720157 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in vfs_coredump
2025/08/12 00:38 upstream 8f5ae30d69d7 c06e8995 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in vfs_coredump
2025/08/05 06:20 upstream d2eedaa3909b abdcb213 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in vfs_coredump
2025/08/05 00:21 upstream d2eedaa3909b f5bcc8dc .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in vfs_coredump
2025/08/01 01:00 upstream 260f6f4fda93 0c075d67 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in vfs_coredump
2025/07/31 18:02 upstream 260f6f4fda93 3526e777 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in vfs_coredump
2025/09/18 15:46 linux-next ae2d20002576 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in vfs_coredump
2025/09/10 21:16 linux-next 5f540c4aade9 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in vfs_coredump
2025/09/07 12:07 linux-next be5d4872e528 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in vfs_coredump
2025/08/25 06:16 linux-next 7fa4d8dc380f bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in vfs_coredump
2025/08/20 11:18 linux-next 5303936d609e 79512909 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in vfs_coredump
2025/08/17 12:29 linux-next 931e46dcbc7e 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in vfs_coredump
2025/07/28 11:10 linux-next d086c886ceb9 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in vfs_coredump
* Struck through repros no longer work on HEAD.