Hi, We found a bug in Linux 6.10. This is likely a mutex corruption bug, where the mutex's internal state has been compromised, leading to an integrity check failure. The bug occurs in https://elixir.bootlin.com/linux/v6.10/source/security/integrity/ima/ima_main.c#L269. The bug report and syzkaller reproducer are as follows: Bug report: DEBUG_LOCKS_WARN_ON(lock->magic != lock) WARNING: CPU: 0 PID: 8057 at kernel/locking/mutex.c:587 __mutex_lock_common kernel/locking/mutex.c:587 [inline] WARNING: CPU: 0 PID: 8057 at kernel/locking/mutex.c:587 __mutex_lock+0xc2d/0xd50 kernel/locking/mutex.c:752 Modules linked in: CPU: 0 PID: 8057 Comm: cron Not tainted 6.10.0 #13 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:__mutex_lock_common kernel/locking/mutex.c:587 [inline] RIP: 0010:__mutex_lock+0xc2d/0xd50 kernel/locking/mutex.c:752 Code: 04 20 84 c0 0f 85 13 01 00 00 83 3d fc e5 23 04 00 0f 85 e9 f4 ff ff 48 c7 c7 60 70 4c 8b 48 c7 c6 e0 70 4c 8b e8 83 f4 54 f6 <0f> 0b e9 cf f4 ff ff 0f 0b e9 dc f8 ff ff 0f 0b e9 5b f5 ff ff 48 RSP: 0018:ffffc9000aa77380 EFLAGS: 00010246 RAX: 26a6b2d2d0cdac00 RBX: 0000000000000000 RCX: ffff8880241e5a00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000aa774d0 R08: ffffffff8155a25a R09: 1ffff1100c74519a R10: dffffc0000000000 R11: ffffed100c74519b R12: dffffc0000000000 R13: ffff888020efc330 R14: 0000000000000000 R15: 1ffff9200154eeb8 FS: 00007f902ffb1840(0000) GS:ffff888063a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f902fb7e06a CR3: 0000000018c3c000 CR4: 0000000000350ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> process_measurement+0x536/0x1ff0 security/integrity/ima/ima_main.c:269 ima_file_check+0xec/0x170 security/integrity/ima/ima_main.c:572 security_file_post_open+0x51/0xb0 security/security.c:2982 do_open fs/namei.c:3656 [inline] path_openat+0x2c0b/0x3580 fs/namei.c:3813 do_filp_open+0x22d/0x480 fs/namei.c:3840 do_sys_openat2+0x13a/0x1c0 fs/open.c:1413 do_sys_open fs/open.c:1428 [inline] __do_sys_openat fs/open.c:1444 [inline] __se_sys_openat fs/open.c:1439 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1439 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x7e/0x150 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x67/0x6f RIP: 0033:0x7f903019a167 Code: 25 00 00 41 00 3d 00 00 41 00 74 47 64 8b 04 25 18 00 00 00 85 c0 75 6b 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 95 00 00 00 48 8b 4c 24 28 64 48 2b 0c 25 RSP: 002b:00007fff194600a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000564dd2fb9cf0 RCX: 00007f903019a167 RDX: 0000000000000000 RSI: 00007f902fb7e103 RDI: 00000000ffffff9c RBP: 00007f902fb7e103 R08: 0000000000000008 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000564dd2fb9cf0 R14: 0000000000000001 R15: 0000000000000000 </TASK> Syzkaller reproducer: # {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:true Sysctl:true Swap:false UseTmpDir:true HandleSegv:true Trace:false LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}} r0 = openat$ptmx(0xffffffffffffff9c, 0x0, 0x141040, 0x0) ioctl$TIOCSETD(r0, 0x5423, 0x0) mmap$IORING_OFF_CQ_RING(&(0x7f0000ffc000/0x4000)=nil, 0x4000, 0x2, 0x20031, 0xffffffffffffffff, 0x8000000) mmap$IORING_OFF_SQ_RING(&(0x7f0000ff4000/0xc000)=nil, 0xc000, 0xe, 0x12, 0xffffffffffffffff, 0x0) openat$sndseq(0xffffffffffffff9c, 0x0, 0x902) write$syz_spec_18446744072532934322_80(0xffffffffffffffff, &(0x7f0000000000)="2b952480c7ca55097d1707935ba64b20f3026c03d658026b81bf264340512b3cb4e01afda2de754299ea7a113343ab7b9bda2fc0a2e2cdbfecbca0233a0772b12ebde5d98a1203cb871672dff7e4c86ec1dccef0a76312fbe8d45dc2bd0f8fc2ebeb2a6be6a300916c5281da2c1ef64d66267091b82429976c019da3645557ed1d439c5a637f6bf58c53bc414539dd87c69098d671402586b631f9ac5c2fe9cedc281a6f005b5c4d1dd5ed9be400", 0xb4) r1 = syz_open_dev$sg(&(0x7f00000003c0), 0x0, 0x8000) ioctl$syz_spec_1724254976_2866(r1, 0x1, &(0x7f0000000080)={0x0, 0x2, [0x85, 0x8, 0x15, 0xd]}) ioctl$KDGKBDIACR(0xffffffffffffffff, 0x4bfa, 0x0) -- Yours sincerely, Xingyu
