syzbot


WARNING in file_seek_cur_needs_f_lock (2)

Status: moderation: reported on 2025/07/03 19:38
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+bb055f21f07d44ad4f1e@syzkaller.appspotmail.com
First crash: 27d, last: 27d
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in file_seek_cur_needs_f_lock overlayfs ext4 -1 C done 10 61d 111d 28/29 fixed on 2025/06/10 16:19

Sample crash report:
loop0: detected capacity change from 0 to 8
------------[ cut here ]------------
WARNING: CPU: 0 PID: 7248 at fs/file.c:1202 file_seek_cur_needs_f_lock+0x124/0x138 fs/file.c:1201
Modules linked in:
CPU: 0 UID: 0 PID: 7248 Comm: syz.0.88 Not tainted 6.16.0-rc2-syzkaller-g9aa9b43d689e #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : file_seek_cur_needs_f_lock+0x124/0x138 fs/file.c:1201
lr : file_seek_cur_needs_f_lock+0x124/0x138 fs/file.c:1201
sp : ffff80009c1a7c80
x29: ffff80009c1a7c80 x28: ffff0000d01ebd00 x27: 0000000000000004
x26: 1fffe0001a03d7a0 x25: 1ffff00013834fd6 x24: dfff800000000000
x23: 0000000000000001 x22: 0000000000000000 x21: bfffffffffffffff
x20: 0000000000000000 x19: ffff0000cf08cc40 x18: 0000000000000000
x17: 0000000000000000 x16: ffff80008aecb76c x15: 0000000000000001
x14: 1fffe00019e1199a x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000080000 x10: 00000000000000c8 x9 : ffff8000a4e89000
x8 : 00000000000000c9 x7 : ffff800080db6574 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff800080516ad4
x2 : 0000000000000000 x1 : 0000000000000008 x0 : 0000000000000000
Call trace:
 file_seek_cur_needs_f_lock+0x124/0x138 fs/file.c:1201 (P)
 generic_file_llseek_size+0xc0/0x454 fs/read_write.c:178
 generic_file_llseek+0xc4/0xdc fs/read_write.c:248
 vfs_llseek fs/read_write.c:389 [inline]
 ksys_lseek fs/read_write.c:402 [inline]
 __do_sys_lseek fs/read_write.c:412 [inline]
 __se_sys_lseek fs/read_write.c:410 [inline]
 __arm64_sys_lseek+0x13c/0x1c0 fs/read_write.c:410
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
irq event stamp: 1126
hardirqs last  enabled at (1125): [<ffff8000801fd600>] local_daif_restore+0x1c/0x3c arch/arm64/include/asm/daifflags.h:75
hardirqs last disabled at (1126): [<ffff80008aec67ac>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:511
softirqs last  enabled at (1120): [<ffff8000801fcf10>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (1118): [<ffff8000801fcedc>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/29 19:33 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 9aa9b43d689e fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in file_seek_cur_needs_f_lock
* Struck through repros no longer work on HEAD.