syzbot


WARNING in do_new_mount (6)

Status: moderation: reported on 2026/02/18 14:16
Subsystems: fs
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+aa9301d3b66961eb2421@syzkaller.appspotmail.com
First crash: 109d, last: 2d06h
✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision Error
faead6e8-02da-431d-a649-5ea8a590208e assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ WARNING in do_new_mount (6) 2026/05/31 16:09 2026/05/31 16:09 2026/05/31 17:18 6b4a844333e83556da95d61d7f207e7ef5cd4bc6
0dd1d590-dccc-4a13-87e6-f54787afc514 assessment-security 💥 WARNING in do_new_mount (6) 2026/05/15 05:28 2026/05/15 05:28 2026/05/15 05:30 6ccb967e465e832a7bfd7a116ad00d52a0923a5d failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/ea6319647410b1260ea344b6710ec8b631a15462" "-s" "bzImage" "compile_commands.json"]: exit status 2 Root cause: error: unable to open output file 'drivers/clk/clk-devres.o': 'No such file or directory' error: unable to open output file 'drivers/clk/clk-bulk.o': 'No such file or directory' /app/workdir/cache/src/fdb7cb6bb7b27f7e6d7ef669765813dd83c15406/lib/maple_tree.c:3514:20: warning: stack frame size (2424) exceeds limit (2048) in 'mas_wr_store_entry' [-Wframe-larger-than] 3514 | static inline void mas_wr_store_entry(struct ma_wr_state *wr_mas) | ^ 1 warning generated. /app/workdir/cache/src/fdb7cb6bb7b27f7e6d7ef669765813dd83c15406/sound/usb/mixer_s1810c.c:634:5: warning: stack frame size (2360) exceeds limit (2048) in 'snd_sc1810_init_mixer' [-Wframe-larger-than] 634 | int snd_sc1810_init_mixer(struct usb_mixer_interface *mixer) | ^ 1 warning generated. mkdir: cannot create directory 'sound/soc/bcm': No space left on device ar: sound/soc/bcm/built-in.a: No such file or directory make[6]: *** [/app/workdir/cache/src/fdb7cb6bb7b27f7e6d7ef669765813dd83c15406/scripts/Makefile.build:477: sound/soc/bcm/built-in.a] Error 1 make[5]: *** [/app/workdir/cache/src/fdb7cb6bb7b27f7e6d7ef669765813dd83c15406/scripts/Makefile.build:548: sound/soc/bcm] Error 2 make[4]: *** [/app/workdir/cache/src/fdb7cb6bb7b27f7e6d7ef669765813dd83c15406/scripts/Makefile.build:548: sound/soc] Error 2 make[4]: *** Waiting for unfinished jobs.... fixdep: not all data was written to the output make[5]: *** [/app/workdir/cache/src/fdb7cb6bb7b27f7e6d7ef669765813dd83c15406/scripts/Makefile.build:289: arch/x86/kernel/kdebugfs.o] Error 1 make[5]: *** Deleting file 'arch/x86/kernel/kdebugfs.o' make[4]: *** [/app/workdir/cache/src/fdb7cb6bb7b27f7e6d7ef669765813dd83c15406/scripts/Makefile.build:548: arch/x86/kernel] Error 2 make[4]: *** Waiting for unfinished jobs.... fatal error: error in backend: IO failure on output stream: No space left on device PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script. Stack dump: 0. Program arguments: /usr/bin/clang --target=x86_64-linux-gnu -fintegrated-as -Werror=unknown-warning-option -Werror=ignored-optimization-argument -Werror=option-ignored -Werror=unused-command-line-argument -fmacro-prefix-map=/app/workdir/cache/src/fdb7cb6bb7b27f7e6d7ef669765813dd83c15406/= -fshort-wchar -funsigned-char -fno-common -fno-PIE -fno-strict-aliasing -std=gnu11 -fms-extensions -Wno-gnu -Wno-microsoft-anon-tag -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx -mno-sse4a -fcf-protection=branch -fno-jump-tables -m64 -falign-loops=1 -mno-80387 -mno-fp-ret-in-387 -mstack-alignment=8 -mskip-rax-setup -march=x86-64 -mtune=generic -mno-red-zone -mcmodel=kernel -mstack-protector-guard-reg=gs -mstack-protector-guard-symbol=__ref_stack_chk_guard -Wno-sign-compare -fno-asynchronous-unwind-tables -mretpoline-external-thunk -mindirect-branch-cs-prefix -mfunction-return=thunk-extern -fpatchable-function-entry=16,16 -fno-delete-null-pointer-checks -O2 -fstack-protector-strong -fomit-frame-pointer -ftrivial-auto-var-init=zero -fno-stack-clash-protection -falign-functions=16 -fstrict-flex-arrays=3 -fno-strict-overflow -fno-stack-check -fno-builtin-wcslen -Wall -Wextra -Wundef -Werror=implicit-function-declaration -Werror=implicit-int -Werror=return-type -Werror=strict-prototypes -Wno-format-security -Wno-trigraphs -Wno-frame-address -Wno-address-of-packed-member -Wmissing-declarations -Wmissing-prototypes -Wframe-larger-than=2048 -Wno-format-overflow-non-kprintf -Wno-format-truncation-non-kprintf -Wno-default-const-init-unsafe -Wno-type-limits -Wno-pointer-sign -Wcast-function-type -Wno-unterminated-string-initialization -Wimplicit-fallthrough -Werror=date-time -Werror=incompatible-pointer-types -Wenum-conversion -Wunused -Wno-unused-but-set-varia
58385d5e-6dc3-4633-9afa-009a6e06e4da repro WARNING in do_new_mount (6) 2026/03/07 03:20 2026/03/07 03:20 2026/03/07 03:29 31e9c887f7dc24e04b3ca70d0d54fc34141844b0
Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in do_new_mount -1 2 1017d 1035d 0/3 auto-obsoleted due to no activity on 2023/11/29 20:19
linux-6.1 WARNING in do_new_mount (2) -1 1 181d 181d 0/3 auto-obsoleted due to no activity on 2026/03/15 04:54
upstream WARNING in do_new_mount fs -1 4 1030d 1048d 0/29 auto-obsoleted due to no activity on 2023/11/07 02:18
upstream WARNING in do_new_mount (5) fs -1 1 353d 349d 0/29 auto-obsoleted due to no activity on 2025/09/14 00:27
upstream WARNING in do_new_mount (3) fs -1 1 517d 513d 0/29 auto-obsoleted due to no activity on 2025/03/03 15:54
linux-6.1 WARNING in do_new_mount -1 4 688d 791d 0/3 auto-obsoleted due to no activity on 2024/10/24 11:22
upstream WARNING in do_new_mount (2) fs -1 22 633d 788d 0/29 auto-obsoleted due to no activity on 2024/12/07 21:46
upstream WARNING in do_new_mount (4) fs -1 2 445d 447d 0/29 auto-obsoleted due to no activity on 2025/06/13 20:52

Sample crash report:
------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(rt_mutex_owner(lock) != current)
WARNING: kernel/locking/rtmutex_common.h:193 at debug_rt_mutex_unlock kernel/locking/rtmutex_common.h:193 [inline], CPU#0: syz.3.1107/13502
WARNING: kernel/locking/rtmutex_common.h:193 at rt_mutex_slowunlock+0x6d9/0x8b0 kernel/locking/rtmutex.c:1428, CPU#0: syz.3.1107/13502
Modules linked in:
CPU: 0 UID: 0 PID: 13502 Comm: syz.3.1107 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:debug_rt_mutex_unlock kernel/locking/rtmutex_common.h:193 [inline]
RIP: 0010:rt_mutex_slowunlock+0x6e0/0x8b0 kernel/locking/rtmutex.c:1428
Code: 88 8f 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 c0 01 00 00 83 3d a4 3a 6b 04 00 75 13 48 8d 3d 67 50 6e 04 48 c7 c6 80 f2 4c 8b <67> 48 0f b9 3a 90 e9 2a fa ff ff 90 0f 0b 90 e9 4c fe ff ff be 02
RSP: 0000:ffffc9000501fbc0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff88806d6703a0 RCX: 0000000000080000
RDX: ffffc9001a50d000 RSI: ffffffff8b4cf280 RDI: ffffffff8f8b8cf0
RBP: ffffc9000501fcb0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1f10ee5 R12: dffffc0000000000
R13: 1ffff92000a03f80 R14: 0000000000000246 R15: ffff88806d670350
FS:  00007fdaff6956c0(0000) GS:ffff888126183000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5ace635000 CR3: 0000000038abc000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 inode_unlock include/linux/fs.h:1039 [inline]
 __unlock_mount fs/namespace.c:2803 [inline]
 unlock_mount fs/namespace.c:2813 [inline]
 do_new_mount_fc fs/namespace.c:3781 [inline]
 do_new_mount+0x7c6/0xd30 fs/namespace.c:3834
 do_mount fs/namespace.c:4167 [inline]
 __do_sys_mount fs/namespace.c:4383 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4360
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdb0145ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdaff695028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fdb016d6090 RCX: 00007fdb0145ce59
RDX: 0000200000000040 RSI: 00002000000001c0 RDI: 0000000000000000
RBP: 00007fdb014f2d6f R08: 0000200000000400 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdb016d6128 R14: 00007fdb016d6090 R15: 00007ffd639ce888
 </TASK>
----------------
Code disassembly (best guess):
   0:	88 8f 48 c1 e8 03    	mov    %cl,0x3e8c148(%rdi)
   6:	42 0f b6 04 20       	movzbl (%rax,%r12,1),%eax
   b:	84 c0                	test   %al,%al
   d:	0f 85 c0 01 00 00    	jne    0x1d3
  13:	83 3d a4 3a 6b 04 00 	cmpl   $0x0,0x46b3aa4(%rip)        # 0x46b3abe
  1a:	75 13                	jne    0x2f
  1c:	48 8d 3d 67 50 6e 04 	lea    0x46e5067(%rip),%rdi        # 0x46e508a
  23:	48 c7 c6 80 f2 4c 8b 	mov    $0xffffffff8b4cf280,%rsi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	90                   	nop
  30:	e9 2a fa ff ff       	jmp    0xfffffa5f
  35:	90                   	nop
  36:	0f 0b                	ud2
  38:	90                   	nop
  39:	e9 4c fe ff ff       	jmp    0xfffffe8a
  3e:	be                   	.byte 0xbe
  3f:	02                   	.byte 0x2

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/02 06:36 upstream 6f3ed7fec72f 1095583b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/05/14 09:06 upstream e1914add2799 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/04/29 05:45 upstream dca922e019dd 95008c03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/04/22 16:18 upstream 6596a02b2078 4595e353 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/03/07 13:07 upstream 651690480a96 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/02/20 08:09 upstream 8bf22c33e7a1 17d780d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/02/14 14:05 upstream c22e26bd0906 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in do_new_mount
2026/02/25 16:13 upstream 7dff99b35460 c162cde9 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in do_new_mount
* Struck through repros no longer work on HEAD.