INFO: rcu detected stall in mount

Status: upstream: reported on 2026/07/31 02:07
Reported-by: syzbot+26ab649e6c65b6925289@syzkaller.appspotmail.com
First crash: 2d03h, last: 2d03h
▶ ▼ Similar bugs (13)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_mount (8) prio:low overlayfs 1 syz, C error 40 12d 339d 0/29 upstream: reported C repro on 2025/08/27 13:07
linux-5.15 INFO: rcu detected stall in mount origin:lts-only 1 syz, C error 5 69d 453d 0/3 upstream: reported C repro on 2025/05/05 20:18
linux-6.1 INFO: rcu detected stall in sys_mount origin:lts-only 1 syz, C inconclusive 8 38d 595d 0/3 upstream: reported C repro on 2024/12/14 21:36
upstream INFO: rcu detected stall in __se_sys_mount afs 1 syz, C done done 2 2093d 2217d 15/29 fixed on 2020/12/08 16:15
upstream INFO: rcu detected stall in sys_mount (6) ntfs 1 syz, C inconclusive 82 996d 1769d 0/29 auto-obsoleted due to no activity on 2024/02/18 04:52
upstream INFO: rcu detected stall in sys_mount (4) fs 1 2 2341d 2356d 0/29 auto-closed as invalid on 2020/06/02 15:48
upstream INFO: rcu detected stall in sys_mount (5) afs 1 syz, C done done 10 2131d 2152d 15/29 fixed on 2020/11/16 12:12
linux-5.15 INFO: rcu detected stall in sys_mount 1 2 597d 659d 0/3 auto-obsoleted due to no activity on 2025/03/22 20:11
upstream INFO: rcu detected stall in sys_mount (3) mm 1 6 2432d 2433d 0/29 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in sys_mount nfs 1 1 2838d 2838d 0/29 closed as invalid on 2018/10/29 13:47
upstream INFO: rcu detected stall in sys_mount (7) fs 1 syz, C inconclusive done 41 585d 827d 0/29 auto-obsoleted due to no activity on 2025/03/30 13:11
upstream INFO: rcu detected stall in sys_mount (2) exfat 1 1 2789d 2789d 0/29 closed as dup on 2018/12/12 21:01
android-5-15 BUG: soft lockup in sys_mount origin:lts 1 syz, C error 17 758d 836d 0/2 auto-obsoleted due to no activity on 2024/10/17 05:03

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P11615/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=62877, q=234 ncpus=1)
task:syz.1.1838      state:R  running task     stack:23176 pid:11615 ppid:5774   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7011
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__sanitizer_cov_trace_pc+0x42/0x60 kernel/kcov.c:221
Code: e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 <48> 8b 32 48 8d 7e 01 8b 89 fc 15 00 00 48 39 cf 73 08 48 89 3a 48
RSP: 0018:ffffc9000345f228 EFLAGS: 00000246
RAX: ffffffff812fb319 RBX: ffffc9000345f2c8 RCX: ffff888021e25a00
RDX: ffffc9000d9db000 RSI: 0000000000025e99 RDI: 0000000000025e9a
RBP: ffffc9000345f2f0 R08: ffffc9000345f327 R09: 0000000000000000
R10: ffffc9000345f2c8 R11: fffff5200068be65 R12: ffffc9000345f268
R13: ffffc9000345f2e8 R14: ffffc9000345f2e8 R15: ffff888021e25a00
 get_stack_info+0x29/0x170 arch/x86/kernel/dumpstack_64.c:194
 __unwind_start+0x406/0x730 arch/x86/kernel/unwind_orc.c:729
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xf8/0x190 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
 save_stack+0x125/0x230 mm/page_owner.c:128
 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1182 [inline]
 free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2459
 __slab_free+0x35a/0x400 mm/slub.c:3736
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6a/0x4d0 mm/slab.h:770
 slab_alloc_node mm/slub.c:3495 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x17e/0x2c0 mm/slub.c:3519
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 alloc_buffer_head+0x2d/0x280 fs/buffer.c:3031
 folio_alloc_buffers+0x39b/0x9c0 fs/buffer.c:935
 grow_dev_page fs/buffer.c:1072 [inline]
 grow_buffers fs/buffer.c:1118 [inline]
 __getblk_slow fs/buffer.c:1145 [inline]
 __getblk_gfp+0x2d5/0x620 fs/buffer.c:1439
 __bread_gfp+0x2a/0x330 fs/buffer.c:1473
 sb_bread include/linux/buffer_head.h:326 [inline]
 fat_fill_super+0x1dc4/0x50c0 fs/fat/inode.c:1645
 mount_bdev+0x21c/0x2c0 fs/super.c:1643
 legacy_get_tree+0xea/0x180 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x280 fs/super.c:1764
 do_new_mount+0x24a/0xa40 fs/namespace.c:3386
 do_mount fs/namespace.c:3726 [inline]
 __do_sys_mount fs/namespace.c:3935 [inline]
 __se_sys_mount+0x2e7/0x3d0 fs/namespace.c:3912
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1b7359f28a
RSP: 002b:00007f1b743dee58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f1b743deee0 RCX: 00007f1b7359f28a
RDX: 0000200000000300 RSI: 0000200000000180 RDI: 00007f1b743deea0
RBP: 0000200000000300 R08: 00007f1b743deee0 R09: 0000000000800000
R10: 0000000000800000 R11: 0000000000000246 R12: 0000200000000180
R13: 00007f1b743deea0 R14: 000000000000037f R15: 0000200000000200
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/31 02:06 linux-6.6.y a1153c0deb44 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in mount
* Struck through repros no longer work on HEAD.