Re: [syzbot] possible deadlock in mnt_want_write (2)

Re: [syzbot] possible deadlock in mnt_want_write (2)

[Miklos Szeredi]

[CC: linux-intergrity]

On Tue, 15 Jun 2021 at 18:59, syzbot
<syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    06af8679 coredump: Limit what can interrupt coredumps
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=162f99afd00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=547a5e42ca601229
> dashboard link: https://syzkaller.appspot.com/bug?extid=b42fe626038981fb7bfa
> compiler:       Debian clang version 11.0.1-2
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com
>
> ======================================================
> WARNING: possible circular locking dependency detected
> 5.13.0-rc5-syzkaller #0 Not tainted
> ------------------------------------------------------
> syz-executor.1/21398 is trying to acquire lock:
> ffff8881485a6460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:375
>
> but task is already holding lock:
> ffff888034945bc0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x75a/0x1ba0 security/integrity/ima/ima_main.c:253
>
> which lock already depends on the new lock.
>
>
> the existing dependency chain (in reverse order) is:
>
> -> #1 (&iint->mutex){+.+.}-{3:3}:
>        lock_acquire+0x17f/0x720 kernel/locking/lockdep.c:5512
>        __mutex_lock_common+0x1bf/0x3100 kernel/locking/mutex.c:959
>        __mutex_lock kernel/locking/mutex.c:1104 [inline]
>        mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:1119
>        process_measurement+0x75a/0x1ba0 security/integrity/ima/ima_main.c:253
>        ima_file_check+0xe0/0x130 security/integrity/ima/ima_main.c:499
>        do_open fs/namei.c:3363 [inline]
>        path_openat+0x293d/0x39b0 fs/namei.c:3494
>        do_filp_open+0x221/0x460 fs/namei.c:3521
>        do_sys_openat2+0x124/0x460 fs/open.c:1187
>        do_sys_open fs/open.c:1203 [inline]
>        __do_sys_open fs/open.c:1211 [inline]
>        __se_sys_open fs/open.c:1207 [inline]
>        __x64_sys_open+0x221/0x270 fs/open.c:1207
>        do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47
>        entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> -> #0 (sb_writers#5){.+.+}-{0:0}:
>        check_prev_add kernel/locking/lockdep.c:2938 [inline]
>        check_prevs_add+0x4f9/0x5b60 kernel/locking/lockdep.c:3061
>        validate_chain kernel/locking/lockdep.c:3676 [inline]
>        __lock_acquire+0x4307/0x6040 kernel/locking/lockdep.c:4902
>        lock_acquire+0x17f/0x720 kernel/locking/lockdep.c:5512
>        percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
>        __sb_start_write include/linux/fs.h:1763 [inline]
>        sb_start_write+0x4f/0x180 include/linux/fs.h:1833
>        mnt_want_write+0x3b/0x80 fs/namespace.c:375
>        ovl_maybe_copy_up+0x117/0x180 fs/overlayfs/copy_up.c:996
>        ovl_open+0xa2/0x200 fs/overlayfs/file.c:149
>        do_dentry_open+0x7cb/0x1010 fs/open.c:826
>        vfs_open fs/open.c:940 [inline]
>        dentry_open+0xc6/0x120 fs/open.c:956
>        ima_calc_file_hash+0x157/0x1b00 security/integrity/ima/ima_crypto.c:557
>        ima_collect_measurement+0x283/0x520 security/integrity/ima/ima_api.c:252
>        process_measurement+0xf79/0x1ba0 security/integrity/ima/ima_main.c:330
>        ima_file_check+0xe0/0x130 security/integrity/ima/ima_main.c:499
>        do_open fs/namei.c:3363 [inline]
>        path_openat+0x293d/0x39b0 fs/namei.c:3494
>        do_filp_open+0x221/0x460 fs/namei.c:3521
>        do_sys_openat2+0x124/0x460 fs/open.c:1187
>        do_sys_open fs/open.c:1203 [inline]
>        __do_sys_open fs/open.c:1211 [inline]
>        __se_sys_open fs/open.c:1207 [inline]
>        __x64_sys_open+0x221/0x270 fs/open.c:1207
>        do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47
>        entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> other info that might help us debug this:
>
>  Possible unsafe locking scenario:
>
>        CPU0                    CPU1
>        ----                    ----
>   lock(&iint->mutex);
>                                lock(sb_writers#5);
>                                lock(&iint->mutex);
>   lock(sb_writers#5);
>
>  *** DEADLOCK ***
>
> 1 lock held by syz-executor.1/21398:
>  #0: ffff888034945bc0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x75a/0x1ba0 security/integrity/ima/ima_main.c:253
>
> stack backtrace:
> CPU: 0 PID: 21398 Comm: syz-executor.1 Not tainted 5.13.0-rc5-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:79 [inline]
>  dump_stack+0x202/0x31e lib/dump_stack.c:120
>  print_circular_bug+0xb17/0xdc0 kernel/locking/lockdep.c:2007
>  check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2129
>  check_prev_add kernel/locking/lockdep.c:2938 [inline]
>  check_prevs_add+0x4f9/0x5b60 kernel/locking/lockdep.c:3061
>  validate_chain kernel/locking/lockdep.c:3676 [inline]
>  __lock_acquire+0x4307/0x6040 kernel/locking/lockdep.c:4902
>  lock_acquire+0x17f/0x720 kernel/locking/lockdep.c:5512
>  percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
>  __sb_start_write include/linux/fs.h:1763 [inline]
>  sb_start_write+0x4f/0x180 include/linux/fs.h:1833
>  mnt_want_write+0x3b/0x80 fs/namespace.c:375
>  ovl_maybe_copy_up+0x117/0x180 fs/overlayfs/copy_up.c:996
>  ovl_open+0xa2/0x200 fs/overlayfs/file.c:149
>  do_dentry_open+0x7cb/0x1010 fs/open.c:826
>  vfs_open fs/open.c:940 [inline]
>  dentry_open+0xc6/0x120 fs/open.c:956
>  ima_calc_file_hash+0x157/0x1b00 security/integrity/ima/ima_crypto.c:557
>  ima_collect_measurement+0x283/0x520 security/integrity/ima/ima_api.c:252
>  process_measurement+0xf79/0x1ba0 security/integrity/ima/ima_main.c:330
>  ima_file_check+0xe0/0x130 security/integrity/ima/ima_main.c:499
>  do_open fs/namei.c:3363 [inline]
>  path_openat+0x293d/0x39b0 fs/namei.c:3494
>  do_filp_open+0x221/0x460 fs/namei.c:3521
>  do_sys_openat2+0x124/0x460 fs/open.c:1187
>  do_sys_open fs/open.c:1203 [inline]
>  __do_sys_open fs/open.c:1211 [inline]
>  __se_sys_open fs/open.c:1207 [inline]
>  __x64_sys_open+0x221/0x270 fs/open.c:1207
>  do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47
>  entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x4665d9
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 bc ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f28cc64c188 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
> RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9
> RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000020000200
> RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
> R13: 00007ffdd1759cef R14: 00007f28cc64c300 R15: 0000000000022000
> overlayfs: upperdir is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection.
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

Re: [syzbot] possible deadlock in mnt_want_write (2)

[Mimi Zohar]

[CC'ing Hillf Danton <hdanton@sina.com>]

Hi Miklos,

On Mon, 2021-07-19 at 17:11 +0200, Miklos Szeredi wrote:
> [CC: linux-intergrity]
> 
> On Tue, 15 Jun 2021 at 18:59, syzbot
> <syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com> wrote:
> >
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    06af8679 coredump: Limit what can interrupt coredumps
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=162f99afd00000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=547a5e42ca601229
> > dashboard link: https://syzkaller.appspot.com/bug?extid=b42fe626038981fb7bfa
> > compiler:       Debian clang version 11.0.1-2
> >
> > Unfortunately, I don't have any reproducer for this issue yet.

There was a similar syzbot report and followup discussion [1].  
According to Amir Goldstein,  it's a false positive lockdep warning.  
At this point we understand how to fix the problem, but are waiting for
a reproducer.

thanks,

Mimi

[1] Message-Id: <20210616090142.734-1-hdanton@sina.com>

> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com

Re: [syzbot] possible deadlock in mnt_want_write (2)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    089866061428 Merge tag 'libnvdimm-fixes-5.19-rc5' of git:/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11dd91f0080000
kernel config:  https://syzkaller.appspot.com/x/.config?x=75c9ff14e1db87c0
dashboard link: https://syzkaller.appspot.com/bug?extid=b42fe626038981fb7bfa
compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=167bafc0080000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11aad3e0080000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
5.19.0-rc4-syzkaller-00187-g089866061428 #0 Not tainted
------------------------------------------------------
syz-executor450/3829 is trying to acquire lock:
ffff88807e574460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393

but task is already holding lock:
ffff888074de91a0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x7d2/0x1c10 security/integrity/ima/ima_main.c:260

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&iint->mutex){+.+.}-{3:3}:
       lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5665
       __mutex_lock_common+0x1de/0x26c0 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
       process_measurement+0x7d2/0x1c10 security/integrity/ima/ima_main.c:260
       ima_file_check+0xe7/0x160 security/integrity/ima/ima_main.c:517
       do_open fs/namei.c:3522 [inline]
       path_openat+0x2705/0x2ec0 fs/namei.c:3653
       do_filp_open+0x277/0x4f0 fs/namei.c:3680
       do_sys_openat2+0x13b/0x500 fs/open.c:1278
       do_sys_open fs/open.c:1294 [inline]
       __do_sys_open fs/open.c:1302 [inline]
       __se_sys_open fs/open.c:1298 [inline]
       __x64_sys_open+0x221/0x270 fs/open.c:1298
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x46/0xb0

-> #0 (sb_writers#4){.+.+}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3095 [inline]
       check_prevs_add kernel/locking/lockdep.c:3214 [inline]
       validate_chain+0x185c/0x65c0 kernel/locking/lockdep.c:3829
       __lock_acquire+0x129a/0x1f80 kernel/locking/lockdep.c:5053
       lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5665
       percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
       __sb_start_write include/linux/fs.h:1699 [inline]
       sb_start_write+0x4d/0x1a0 include/linux/fs.h:1774
       mnt_want_write+0x3b/0x80 fs/namespace.c:393
       ovl_maybe_copy_up+0x124/0x190 fs/overlayfs/copy_up.c:1078
       ovl_open+0x106/0x2a0 fs/overlayfs/file.c:152
       do_dentry_open+0x789/0x1040 fs/open.c:848
       vfs_open fs/open.c:981 [inline]
       dentry_open+0xc1/0x120 fs/open.c:997
       ima_calc_file_hash+0x157/0x1cb0 security/integrity/ima/ima_crypto.c:557
       ima_collect_measurement+0x3de/0x850 security/integrity/ima/ima_api.c:292
       process_measurement+0xf87/0x1c10 security/integrity/ima/ima_main.c:337
       ima_file_check+0xe7/0x160 security/integrity/ima/ima_main.c:517
       do_open fs/namei.c:3522 [inline]
       path_openat+0x2705/0x2ec0 fs/namei.c:3653
       do_filp_open+0x277/0x4f0 fs/namei.c:3680
       do_sys_openat2+0x13b/0x500 fs/open.c:1278
       do_sys_open fs/open.c:1294 [inline]
       __do_sys_open fs/open.c:1302 [inline]
       __se_sys_open fs/open.c:1298 [inline]
       __x64_sys_open+0x221/0x270 fs/open.c:1298
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x46/0xb0

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&iint->mutex);
                               lock(sb_writers#4);
                               lock(&iint->mutex);
  lock(sb_writers#4);

 *** DEADLOCK ***

1 lock held by syz-executor450/3829:
 #0: ffff888074de91a0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x7d2/0x1c10 security/integrity/ima/ima_main.c:260

stack backtrace:
CPU: 1 PID: 3829 Comm: syz-executor450 Not tainted 5.19.0-rc4-syzkaller-00187-g089866061428 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 check_noncircular+0x2f7/0x3b0 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3095 [inline]
 check_prevs_add kernel/locking/lockdep.c:3214 [inline]
 validate_chain+0x185c/0x65c0 kernel/locking/lockdep.c:3829
 __lock_acquire+0x129a/0x1f80 kernel/locking/lockdep.c:5053
 lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5665
 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
 __sb_start_write include/linux/fs.h:1699 [inline]
 sb_start_write+0x4d/0x1a0 include/linux/fs.h:1774
 mnt_want_write+0x3b/0x80 fs/namespace.c:393
 ovl_maybe_copy_up+0x124/0x190 fs/overlayfs/copy_up.c:1078
 ovl_open+0x106/0x2a0 fs/overlayfs/file.c:152
 do_dentry_open+0x789/0x1040 fs/open.c:848
 vfs_open fs/open.c:981 [inline]
 dentry_open+0xc1/0x120 fs/open.c:997
 ima_calc_file_hash+0x157/0x1cb0 security/integrity/ima/ima_crypto.c:557
 ima_collect_measurement+0x3de/0x850 security/integrity/ima/ima_api.c:292
 process_measurement+0xf87/0x1c10 security/integrity/ima/ima_main.c:337
 ima_file_check+0xe7/0x160 security/integrity/ima/ima_main.c:517
 do_open fs/namei.c:3522 [inline]
 path_openat+0x2705/0x2ec0 fs/namei.c:3653
 do_filp_open+0x277/0x4f0 fs/namei.c:3680
 do_sys_openat2+0x13b/0x500 fs/open.c:1278
 do_sys_open fs/open.c:1294 [inline]
 __do_sys_open fs/open.c:1302 [inline]
 __se_sys_open fs/open.c:1298 [inline]
 __x64_sys_open+0x221/0x270 fs/open.c:1298
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7faf98402749
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 31 16 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007faf9838e2f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007faf98491270 RCX: 00007faf98402749
RDX: 0000000000000000 RSI: 000000000000000b RDI: 00000000200000c0
RBP: 00007faf98458504 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e
R13: 3d7269647265776f R14: 0079616c7265766f R15: 00007faf98491278
 </TASK>

Re: [syzbot] possible deadlock in mnt_want_write (2)

[Mimi Zohar]

Thank you for the reproducer.  This seems to be a similar false
positive as was discussed:
https://lore.kernel.org/linux-unionfs/000000000000c5b77105b4c3546e@google.com/

thanks,

Mimi

On Sat, 2022-07-02 at 10:27 -0700, syzbot wrote:
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    089866061428 Merge tag 'libnvdimm-fixes-5.19-rc5' of git:/..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=11dd91f0080000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=75c9ff14e1db87c0
> dashboard link: https://syzkaller.appspot.com/bug?extid=b42fe626038981fb7bfa
> compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=167bafc0080000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11aad3e0080000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com
> 
> ======================================================
> WARNING: possible circular locking dependency detected
> 5.19.0-rc4-syzkaller-00187-g089866061428 #0 Not tainted
> ------------------------------------------------------
> syz-executor450/3829 is trying to acquire lock:
> ffff88807e574460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393
> 
> but task is already holding lock:
> ffff888074de91a0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x7d2/0x1c10 security/integrity/ima/ima_main.c:260
> 
> which lock already depends on the new lock.
> 
> 
> the existing dependency chain (in reverse order) is:
> 
> -> #1 (&iint->mutex){+.+.}-{3:3}:
>        lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5665
>        __mutex_lock_common+0x1de/0x26c0 kernel/locking/mutex.c:603
>        __mutex_lock kernel/locking/mutex.c:747 [inline]
>        mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
>        process_measurement+0x7d2/0x1c10 security/integrity/ima/ima_main.c:260
>        ima_file_check+0xe7/0x160 security/integrity/ima/ima_main.c:517
>        do_open fs/namei.c:3522 [inline]
>        path_openat+0x2705/0x2ec0 fs/namei.c:3653
>        do_filp_open+0x277/0x4f0 fs/namei.c:3680
>        do_sys_openat2+0x13b/0x500 fs/open.c:1278
>        do_sys_open fs/open.c:1294 [inline]
>        __do_sys_open fs/open.c:1302 [inline]
>        __se_sys_open fs/open.c:1298 [inline]
>        __x64_sys_open+0x221/0x270 fs/open.c:1298
>        do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>        do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
>        entry_SYSCALL_64_after_hwframe+0x46/0xb0
> 
> -> #0 (sb_writers#4){.+.+}-{0:0}:
>        check_prev_add kernel/locking/lockdep.c:3095 [inline]
>        check_prevs_add kernel/locking/lockdep.c:3214 [inline]
>        validate_chain+0x185c/0x65c0 kernel/locking/lockdep.c:3829
>        __lock_acquire+0x129a/0x1f80 kernel/locking/lockdep.c:5053
>        lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5665
>        percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
>        __sb_start_write include/linux/fs.h:1699 [inline]
>        sb_start_write+0x4d/0x1a0 include/linux/fs.h:1774
>        mnt_want_write+0x3b/0x80 fs/namespace.c:393
>        ovl_maybe_copy_up+0x124/0x190 fs/overlayfs/copy_up.c:1078
>        ovl_open+0x106/0x2a0 fs/overlayfs/file.c:152
>        do_dentry_open+0x789/0x1040 fs/open.c:848
>        vfs_open fs/open.c:981 [inline]
>        dentry_open+0xc1/0x120 fs/open.c:997
>        ima_calc_file_hash+0x157/0x1cb0 security/integrity/ima/ima_crypto.c:557
>        ima_collect_measurement+0x3de/0x850 security/integrity/ima/ima_api.c:292
>        process_measurement+0xf87/0x1c10 security/integrity/ima/ima_main.c:337
>        ima_file_check+0xe7/0x160 security/integrity/ima/ima_main.c:517
>        do_open fs/namei.c:3522 [inline]
>        path_openat+0x2705/0x2ec0 fs/namei.c:3653
>        do_filp_open+0x277/0x4f0 fs/namei.c:3680
>        do_sys_openat2+0x13b/0x500 fs/open.c:1278
>        do_sys_open fs/open.c:1294 [inline]
>        __do_sys_open fs/open.c:1302 [inline]
>        __se_sys_open fs/open.c:1298 [inline]
>        __x64_sys_open+0x221/0x270 fs/open.c:1298
>        do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>        do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
>        entry_SYSCALL_64_after_hwframe+0x46/0xb0
> 
> other info that might help us debug this:
> 
>  Possible unsafe locking scenario:
> 
>        CPU0                    CPU1
>        ----                    ----
>   lock(&iint->mutex);
>                                lock(sb_writers#4);
>                                lock(&iint->mutex);
>   lock(sb_writers#4);
> 
>  *** DEADLOCK ***
> 
> 1 lock held by syz-executor450/3829:
>  #0: ffff888074de91a0 (&iint->mutex){+.+.}-{3:3}, at: process_measurement+0x7d2/0x1c10 security/integrity/ima/ima_main.c:260
> 
> stack backtrace:
> CPU: 1 PID: 3829 Comm: syz-executor450 Not tainted 5.19.0-rc4-syzkaller-00187-g089866061428 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:88 [inline]
>  dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
>  check_noncircular+0x2f7/0x3b0 kernel/locking/lockdep.c:2175
>  check_prev_add kernel/locking/lockdep.c:3095 [inline]
>  check_prevs_add kernel/locking/lockdep.c:3214 [inline]
>  validate_chain+0x185c/0x65c0 kernel/locking/lockdep.c:3829
>  __lock_acquire+0x129a/0x1f80 kernel/locking/lockdep.c:5053
>  lock_acquire+0x1a7/0x400 kernel/locking/lockdep.c:5665
>  percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
>  __sb_start_write include/linux/fs.h:1699 [inline]
>  sb_start_write+0x4d/0x1a0 include/linux/fs.h:1774
>  mnt_want_write+0x3b/0x80 fs/namespace.c:393
>  ovl_maybe_copy_up+0x124/0x190 fs/overlayfs/copy_up.c:1078
>  ovl_open+0x106/0x2a0 fs/overlayfs/file.c:152
>  do_dentry_open+0x789/0x1040 fs/open.c:848
>  vfs_open fs/open.c:981 [inline]
>  dentry_open+0xc1/0x120 fs/open.c:997
>  ima_calc_file_hash+0x157/0x1cb0 security/integrity/ima/ima_crypto.c:557
>  ima_collect_measurement+0x3de/0x850 security/integrity/ima/ima_api.c:292
>  process_measurement+0xf87/0x1c10 security/integrity/ima/ima_main.c:337
>  ima_file_check+0xe7/0x160 security/integrity/ima/ima_main.c:517
>  do_open fs/namei.c:3522 [inline]
>  path_openat+0x2705/0x2ec0 fs/namei.c:3653
>  do_filp_open+0x277/0x4f0 fs/namei.c:3680
>  do_sys_openat2+0x13b/0x500 fs/open.c:1278
>  do_sys_open fs/open.c:1294 [inline]
>  __do_sys_open fs/open.c:1302 [inline]
>  __se_sys_open fs/open.c:1298 [inline]
>  __x64_sys_open+0x221/0x270 fs/open.c:1298
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x46/0xb0
> RIP: 0033:0x7faf98402749
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 31 16 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007faf9838e2f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
> RAX: ffffffffffffffda RBX: 00007faf98491270 RCX: 00007faf98402749
> RDX: 0000000000000000 RSI: 000000000000000b RDI: 00000000200000c0
> RBP: 00007faf98458504 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e
> R13: 3d7269647265776f R14: 0079616c7265766f R15: 00007faf98491278
>  </TASK>
> 

Re: [syzbot] possible deadlock in mnt_want_write (2)

[Mimi Zohar]

Hi Hillf,g

On Wed, 2022-07-06 at 20:10 +0800, Hillf Danton wrote:
> On Tue, 05 Jul 2022 08:53:15 -0400 Mimi Zohar wrote:
> > 
> > Thank you for the reproducer.  This seems to be a similar false
> > positive as was discussed:
> > https://lore.kernel.org/linux-unionfs/000000000000c5b77105b4c3546e@google.com/
> > 
> > thanks,
> > 
> 
> Hi Mimi
> 
> Please pick up the patch attached if it makes sense to you.

The patch itself looks good, but missing from the patch description is
an indication that the lockdep warning is a false positive.  Perhaps
add a "Suggested-by" line crediting Amir.   I'd appreciate your posting
the patch on the mailing list.

thanks!

Mimi

> From: Hillf Danton <hdanton@sina.com>
> Subject: [PATCH] integrity: lockdep annotate of iint->mutex
> 
> This fixes a reported lockdep splat
> 
>         CPU0                    CPU1
>         ----                    ----
> 	lock(&iint->mutex);
> 				lock(sb_writers#4);
> 				lock(&iint->mutex);
> 	lock(sb_writers#4);
>  
> 	*** DEADLOCK ***
> 
> using the method in 4eae06de482b annotating OVL_I(inode)->lock.
> 
> Links: https://lore.kernel.org/linux-unionfs/CAOQ4uxjk4XYuwz5HCmN-Ge=Ld=tM1f7ZxVrd5U1AC2Wisc9MTA@mail.gmail.com/
> Reported-and-tested-by: syzbot <syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com>
> Cc: Mimi Zohar <zohar@linux.ibm.com>
> Cc: Amir Goldstein <amir73il@gmail.com>
> Signed-off-by: Hillf Danton <hdanton@sina.com>
> ---
> 
> --- a/security/integrity/iint.c 
> +++ b/security/integrity/iint.c 
> @@ -85,6 +85,17 @@ static void iint_free(struct integrity_i
>  	kmem_cache_free(iint_cache, iint);
>  }
>  
> +static void iint_annotate_mutex_key(struct integrity_iint_cache *iint, struct inode *inode)
> +{
> +#ifdef CONFIG_LOCKDEP
> +	static struct lock_class_key iint_mutex_key[FILESYSTEM_MAX_STACK_DEPTH];
> +
> +	int depth = inode->i_sb->s_stack_depth;
> +
> +	lockdep_set_class(&iint->mutex, &iint_mutex_key[depth]);
> +#endif
> +}
> +
>  /**
>   * integrity_inode_get - find or allocate an iint associated with an inode
>   * @inode: pointer to the inode
> @@ -114,6 +125,8 @@ struct integrity_iint_cache *integrity_i
>  	if (!iint)
>  		return NULL;
>  
> +	iint_annotate_mutex_key(iint, inode);
> +
>  	write_lock(&integrity_iint_lock);
>  
>  	p = &integrity_iint_tree.rb_node;
> --

Re: [syzbot] possible deadlock in mnt_want_write (2)

[Miklos Szeredi]

#syz set subsystems: intergrity, overlayfs

Re: [syzbot] possible deadlock in mnt_want_write (2)

[syzbot]

> #syz set subsystems: intergrity, overlayfs

The specified label value is incorrect.
"intergrity" is not among the allowed values.
Please use one of the supported label values.

The following labels are suported:
missing-backport, no-reminders, prio: {low, normal, high}, subsystems: {.. see below ..}
The list of subsystems: https://syzkaller.appspot.com/upstream/subsystems?all=true

Re: [syzbot] possible deadlock in mnt_want_write (2)

[Miklos Szeredi]

#syz set subsystems: integrity, overlayfs


On Tue, 6 Jun 2023 at 11:12, syzbot
<syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com> wrote:
>
> > #syz set subsystems: intergrity, overlayfs
>
> The specified label value is incorrect.
> "intergrity" is not among the allowed values.
> Please use one of the supported label values.
>
> The following labels are suported:
> missing-backport, no-reminders, prio: {low, normal, high}, subsystems: {.. see below ..}
> The list of subsystems: https://syzkaller.appspot.com/upstream/subsystems?all=true
>

Re: [syzbot] [integrity] [overlayfs] possible deadlock in mnt_want_write (2)

[syzbot]

syzbot has bisected this issue to:

commit 708fa01597fa002599756bf56a96d0de1677375c
Author: Miklos Szeredi <mszeredi@redhat.com>
Date:   Mon Apr 12 10:00:37 2021 +0000

    ovl: allow upperdir inside lowerdir

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=17ad11b2680000
start commit:   3aba70aed91f Merge tag 'gpio-fixes-for-v6.6-rc3' of git://..
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=146d11b2680000
console output: https://syzkaller.appspot.com/x/log.txt?x=106d11b2680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e4ca82a1bedd37e4
dashboard link: https://syzkaller.appspot.com/bug?extid=b42fe626038981fb7bfa
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1304fba6680000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13cec0dc680000

Reported-by: syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com
Fixes: 708fa01597fa ("ovl: allow upperdir inside lowerdir")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Re: [syzbot] [integrity] [overlayfs] possible deadlock in mnt_want_write (2)

[Amir Goldstein]

On Wed, Oct 4, 2023 at 7:45 PM syzbot
<syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com> wrote:
>
> syzbot has bisected this issue to:
>
> commit 708fa01597fa002599756bf56a96d0de1677375c
> Author: Miklos Szeredi <mszeredi@redhat.com>
> Date:   Mon Apr 12 10:00:37 2021 +0000
>
>     ovl: allow upperdir inside lowerdir
>
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=17ad11b2680000
> start commit:   3aba70aed91f Merge tag 'gpio-fixes-for-v6.6-rc3' of git://..
> git tree:       upstream
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=146d11b2680000
> console output: https://syzkaller.appspot.com/x/log.txt?x=106d11b2680000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=e4ca82a1bedd37e4
> dashboard link: https://syzkaller.appspot.com/bug?extid=b42fe626038981fb7bfa
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1304fba6680000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13cec0dc680000
>
> Reported-by: syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com
> Fixes: 708fa01597fa ("ovl: allow upperdir inside lowerdir")
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection

#syz test: https://github.com/amir73il/linux ima-ovl-fix

Re: [syzbot] [integrity] [overlayfs] possible deadlock in mnt_want_write (2)

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

.11
[   11.711476][    T1] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[   11.717652][    T1] Bluetooth: BNEP filters: protocol multicast
[   11.723764][    T1] Bluetooth: BNEP socket layer initialized
[   11.729798][    T1] Bluetooth: CMTP (CAPI Emulation) ver 1.0
[   11.735800][    T1] Bluetooth: CMTP socket layer initialized
[   11.741657][    T1] Bluetooth: HIDP (Human Interface Emulation) ver 1.2
[   11.748518][    T1] Bluetooth: HIDP socket layer initialized
[   11.758808][    T1] NET: Registered PF_RXRPC protocol family
[   11.764714][    T1] Key type rxrpc registered
[   11.769426][    T1] Key type rxrpc_s registered
[   11.774975][    T1] NET: Registered PF_KCM protocol family
[   11.781399][    T1] lec:lane_module_init: lec.c: initialized
[   11.787210][    T1] mpoa:atm_mpoa_init: mpc.c: initialized
[   11.793325][    T1] l2tp_core: L2TP core driver, V2.0
[   11.798593][    T1] l2tp_ppp: PPPoL2TP kernel driver, V2.0
[   11.804282][    T1] l2tp_ip: L2TP IP encapsulation support (L2TPv3)
[   11.810911][    T1] l2tp_netlink: L2TP netlink interface
[   11.816532][    T1] l2tp_eth: L2TP ethernet pseudowire support (L2TPv3)
[   11.823862][    T1] l2tp_ip6: L2TP IP encapsulation support for IPv6 (L2TPv3)
[   11.831528][    T1] NET: Registered PF_PHONET protocol family
[   11.837777][    T1] 8021q: 802.1Q VLAN Support v1.8
[   11.855888][    T1] DCCP: Activated CCID 2 (TCP-like)
[   11.861493][    T1] DCCP: Activated CCID 3 (TCP-Friendly Rate Control)
[   11.868489][    T1] DCCP is deprecated and scheduled to be removed in 2025, please contact the netdev mailing list
[   11.879600][    T1] sctp: Hash tables configured (bind 32/56)
[   11.886970][    T1] NET: Registered PF_RDS protocol family
[   11.893414][    T1] Registered RDS/infiniband transport
[   11.900057][    T1] Registered RDS/tcp transport
[   11.904815][    T1] tipc: Activated (version 2.0.0)
[   11.910959][    T1] NET: Registered PF_TIPC protocol family
[   11.917541][    T1] tipc: Started in single node mode
[   11.923606][    T1] NET: Registered PF_SMC protocol family
[   11.929592][    T1] 9pnet: Installing 9P2000 support
[   11.935356][    T1] NET: Registered PF_CAIF protocol family
[   11.948223][    T1] NET: Registered PF_IEEE802154 protocol family
[   11.954672][    T1] Key type dns_resolver registered
[   11.959869][    T1] Key type ceph registered
[   11.964886][    T1] libceph: loaded (mon/osd proto 15/24)
[   11.971970][    T1] batman_adv: B.A.T.M.A.N. advanced 2023.3 (compatibility version 15) loaded
[   11.981263][    T1] openvswitch: Open vSwitch switching datapath
[   11.991164][    T1] NET: Registered PF_VSOCK protocol family
[   11.997270][    T1] mpls_gso: MPLS GSO support
[   12.019850][    T1] IPI shorthand broadcast: enabled
[   12.025183][    T1] AVX2 version of gcm_enc/dec engaged.
[   12.031096][    T1] AES CTR mode by8 optimization enabled
[   13.986311][    T1] sched_clock: Marking stable (13940030159, 37368238)->(13987518566, -10120169)
[   14.000622][    T1] registered taskstats version 1
[   14.020069][    T1] Loading compiled-in X.509 certificates
[   14.031543][    T1] Loaded X.509 cert 'Build time autogenerated kernel key: 2d553f2396bceba4be328de3fad0b481a51ca3cf'
[   14.045807][    T1] zswap: loaded using pool lzo/zbud
[   14.257081][    T1] debug_vm_pgtable: [debug_vm_pgtable         ]: Validating architecture page table helpers
[   16.606589][    T1] Key type .fscrypt registered
[   16.611425][    T1] Key type fscrypt-provisioning registered
[   16.624007][    T1] kAFS: Red Hat AFS client v0.1 registering.
[   16.646715][    T1] Btrfs loaded, assert=on, ref-verify=on, zoned=yes, fsverity=yes
[   16.656542][    T1] Key type big_key registered
[   16.664108][    T1] Key type encrypted registered
[   16.669211][    T1] ima: No TPM chip found, activating TPM-bypass!
[   16.675572][    T1] Loading compiled-in module X.509 certificates
[   16.684589][    T1] Loaded X.509 cert 'Build time autogenerated kernel key: 2d553f2396bceba4be328de3fad0b481a51ca3cf'
[   16.695647][    T1] ima: Allocated hash algorithm: sha256
[   16.701654][    T1] ima: No architecture policies found
[   16.707848][    T1] evm: Initialising EVM extended attributes:
[   16.714189][    T1] evm: security.selinux (disabled)
[   16.719369][    T1] evm: security.SMACK64
[   16.723503][    T1] evm: security.SMACK64EXEC
[   16.728365][    T1] evm: security.SMACK64TRANSMUTE
[   16.733278][    T1] evm: security.SMACK64MMAP
[   16.737801][    T1] evm: security.apparmor (disabled)
[   16.742978][    T1] evm: security.ima
[   16.746763][    T1] evm: security.capability
[   16.751272][    T1] evm: HMAC attrs: 0x1
[   16.757582][    T1] PM:   Magic number: 11:141:828
[   16.762692][    T1] video4linux v4l-touch6: hash matches
[   16.768621][    T1] tty ptyt8: hash matches
[   16.772947][    T1] tty ptyqb: hash matches
[   16.779976][    T1] printk: console [netcon0] enabled
[   16.785201][    T1] netconsole: network logging started
[   16.791177][    T1] gtp: GTP module loaded (pdp ctx size 104 bytes)
[   16.799026][    T1] rdma_rxe: loaded
[   16.803522][    T1] cfg80211: Loading compiled-in X.509 certificates for regulatory database
[   16.814312][    T1] Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
[   16.821808][    T1] clk: Disabling unused clocks
[   16.822972][ T2520] platform regulatory.0: Direct firmware load for regulatory.db failed with error -2
[   16.826718][    T1] ALSA device list:
[   16.836181][ T2520] platform regulatory.0: Falling back to sysfs fallback for: regulatory.db
[   16.849196][    T1]   #0: Dummy 1
[   16.852687][    T1]   #1: Loopback 1
[   16.856406][    T1]   #2: Virtual MIDI Card 1
[   16.864429][    T1] md: Waiting for all devices to be available before autodetect
[   16.872287][    T1] md: If you don't use raid, use raid=noautodetect
[   16.878935][    T1] md: Autodetecting RAID arrays.
[   16.883975][    T1] md: autorun ...
[   16.887676][    T1] md: ... autorun DONE.
[   16.961157][    T1] EXT4-fs (sda1): mounted filesystem 5941fea2-f5fa-4b4e-b5ef-9af118b27b95 ro with ordered data mode. Quota mode: none.
[   16.973957][    T1] VFS: Mounted root (ext4 filesystem) readonly on device 8:1.
[   17.007193][    T1] devtmpfs: mounted
[   17.026225][    T1] Freeing unused kernel image (initmem) memory: 2884K
[   17.033318][    T1] Write protecting the kernel read-only data: 196608k
[   17.044849][    T1] Freeing unused kernel image (rodata/data gap) memory: 1780K
[   17.152701][    T1] x86/mm: Checked W+X mappings: passed, no W+X pages found.
[   17.165765][    T1] Failed to set sysctl parameter 'max_rcu_stall_to_panic=1': parameter not found
[   17.175611][    T1] Run /sbin/init as init process
[   17.221897][    T1] ------------[ cut here ]------------
[   17.227549][    T1] WARNING: CPU: 1 PID: 1 at security/integrity/iint.c:85 integrity_inode_get+0x499/0x580
[   17.237529][    T1] Modules linked in:
[   17.241431][    T1] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 6.6.0-rc4-syzkaller-00001-g79be50b1a644 #0
[   17.251093][    T1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
[   17.261192][    T1] RIP: 0010:integrity_inode_get+0x499/0x580
[   17.267086][    T1] Code: eb 11 e8 ba 30 8c fd 48 c7 c7 60 e4 92 8d e8 be 1e d6 06 4c 89 e0 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 97 30 8c fd <0f> 0b 31 db e9 b0 fd ff ff 44 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c
[   17.287095][    T1] RSP: 0000:ffffc900000678f0 EFLAGS: 00010293
[   17.293214][    T1] RAX: ffffffff8401db19 RBX: 00000000ffffffff RCX: ffff888015e58000
[   17.301239][    T1] RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0000000000000001
[   17.309277][    T1] RBP: ffff88801db8aad8 R08: ffffffff8401d8c4 R09: 0000000000000000
[   17.317271][    T1] R10: ffff88802871d088 R11: ffffed10050e3a13 R12: ffff88802871d000
[   17.325268][    T1] R13: ffff88802871d0d0 R14: dffffc0000000000 R15: ffff88801db8aab0
[   17.333277][    T1] FS:  0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
[   17.342239][    T1] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   17.348852][    T1] CR2: 0000000000000000 CR3: 000000000d130000 CR4: 00000000003506e0
[   17.356912][    T1] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   17.364907][    T1] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   17.372924][    T1] Call Trace:
[   17.376200][    T1]  <TASK>
[   17.379331][    T1]  ? __warn+0x162/0x4a0
[   17.383486][    T1]  ? integrity_inode_get+0x499/0x580
[   17.388813][    T1]  ? report_bug+0x2b3/0x500
[   17.393312][    T1]  ? integrity_inode_get+0x499/0x580
[   17.398712][    T1]  ? handle_bug+0x3d/0x70
[   17.403043][    T1]  ? exc_invalid_op+0x1a/0x50
[   17.407747][    T1]  ? asm_exc_invalid_op+0x1a/0x20
[   17.412768][    T1]  ? integrity_inode_get+0x244/0x580
[   17.418159][    T1]  ? integrity_inode_get+0x499/0x580
[   17.423885][    T1]  ? integrity_inode_get+0x499/0x580
[   17.429210][    T1]  process_measurement+0x44d/0x1cf0
[   17.434430][    T1]  ? ima_file_mmap+0x2b0/0x2b0
[   17.439238][    T1]  ? lockdep_hardirqs_on_prepare+0x43c/0x7a0
[   17.445312][    T1]  ? print_irqtrace_events+0x220/0x220
[   17.450839][    T1]  ? smack_current_getsecid_subj+0x22/0xf0
[   17.456665][    T1]  ima_bprm_check+0x128/0x2b0
[   17.461376][    T1]  ? ima_file_mprotect+0x630/0x630
[   17.466596][    T1]  ? tomoyo_bprm_check_security+0x157/0x170
[   17.472718][    T1]  ? bpf_lsm_bprm_check_security+0x9/0x10
[   17.478532][    T1]  bprm_execve+0x8c7/0x17c0
[   17.483078][    T1]  ? alloc_bprm+0x900/0x900
[   17.487748][    T1]  ? copy_string_kernel+0x1c9/0x1f0
[   17.492960][    T1]  kernel_execve+0x8ea/0xa10
[   17.497605][    T1]  ? rest_init+0x300/0x300
[   17.502038][    T1]  kernel_init+0xde/0x2a0
[   17.506364][    T1]  ret_from_fork+0x48/0x80
[   17.510808][    T1]  ? rest_init+0x300/0x300
[   17.515229][    T1]  ret_from_fork_asm+0x11/0x20
[   17.520045][    T1]  </TASK>
[   17.523071][    T1] Kernel panic - not syncing: kernel: panic_on_warn set ...
[   17.530373][    T1] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 6.6.0-rc4-syzkaller-00001-g79be50b1a644 #0
[   17.540081][    T1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
[   17.550128][    T1] Call Trace:
[   17.553400][    T1]  <TASK>
[   17.556320][    T1]  dump_stack_lvl+0x1e7/0x2d0
[   17.561004][    T1]  ? nf_tcp_handle_invalid+0x650/0x650
[   17.566476][    T1]  ? panic+0x770/0x770
[   17.570546][    T1]  ? vscnprintf+0x5d/0x80
[   17.574964][    T1]  panic+0x30f/0x770
[   17.578877][    T1]  ? __warn+0x171/0x4a0
[   17.583027][    T1]  ? __memcpy_flushcache+0x2b0/0x2b0
[   17.588307][    T1]  ? ret_from_fork_asm+0x11/0x20
[   17.593262][    T1]  __warn+0x314/0x4a0
[   17.597275][    T1]  ? integrity_inode_get+0x499/0x580
[   17.602597][    T1]  report_bug+0x2b3/0x500
[   17.606935][    T1]  ? integrity_inode_get+0x499/0x580
[   17.612218][    T1]  handle_bug+0x3d/0x70
[   17.616365][    T1]  exc_invalid_op+0x1a/0x50
[   17.620862][    T1]  asm_exc_invalid_op+0x1a/0x20
[   17.625711][    T1] RIP: 0010:integrity_inode_get+0x499/0x580
[   17.631598][    T1] Code: eb 11 e8 ba 30 8c fd 48 c7 c7 60 e4 92 8d e8 be 1e d6 06 4c 89 e0 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 97 30 8c fd <0f> 0b 31 db e9 b0 fd ff ff 44 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c
[   17.651202][    T1] RSP: 0000:ffffc900000678f0 EFLAGS: 00010293
[   17.657365][    T1] RAX: ffffffff8401db19 RBX: 00000000ffffffff RCX: ffff888015e58000
[   17.665448][    T1] RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0000000000000001
[   17.673405][    T1] RBP: ffff88801db8aad8 R08: ffffffff8401d8c4 R09: 0000000000000000
[   17.681392][    T1] R10: ffff88802871d088 R11: ffffed10050e3a13 R12: ffff88802871d000
[   17.689449][    T1] R13: ffff88802871d0d0 R14: dffffc0000000000 R15: ffff88801db8aab0
[   17.697440][    T1]  ? integrity_inode_get+0x244/0x580
[   17.702744][    T1]  ? integrity_inode_get+0x499/0x580
[   17.708088][    T1]  process_measurement+0x44d/0x1cf0
[   17.713299][    T1]  ? ima_file_mmap+0x2b0/0x2b0
[   17.718152][    T1]  ? lockdep_hardirqs_on_prepare+0x43c/0x7a0
[   17.724212][    T1]  ? print_irqtrace_events+0x220/0x220
[   17.729771][    T1]  ? smack_current_getsecid_subj+0x22/0xf0
[   17.735568][    T1]  ima_bprm_check+0x128/0x2b0
[   17.740240][    T1]  ? ima_file_mprotect+0x630/0x630
[   17.745342][    T1]  ? tomoyo_bprm_check_security+0x157/0x170
[   17.751221][    T1]  ? bpf_lsm_bprm_check_security+0x9/0x10
[   17.756946][    T1]  bprm_execve+0x8c7/0x17c0
[   17.761458][    T1]  ? alloc_bprm+0x900/0x900
[   17.765952][    T1]  ? copy_string_kernel+0x1c9/0x1f0
[   17.771134][    T1]  kernel_execve+0x8ea/0xa10
[   17.775738][    T1]  ? rest_init+0x300/0x300
[   17.780153][    T1]  kernel_init+0xde/0x2a0
[   17.784472][    T1]  ret_from_fork+0x48/0x80
[   17.788876][    T1]  ? rest_init+0x300/0x300
[   17.793276][    T1]  ret_from_fork_asm+0x11/0x20
[   17.798036][    T1]  </TASK>
[   17.801282][    T1] Kernel Offset: disabled
[   17.805673][    T1] Rebooting in 86400 seconds..


syzkaller build log:
go env (err=<nil>)
GO111MODULE="auto"
GOARCH="amd64"
GOBIN=""
GOCACHE="/syzkaller/.cache/go-build"
GOENV="/syzkaller/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/syzkaller/jobs-2/linux/gopath/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/syzkaller/jobs-2/linux/gopath"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.20.1"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/syzkaller/jobs-2/linux/gopath/src/github.com/google/syzkaller/go.mod"
GOWORK=""
CGO_CFLAGS="-O2 -g"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-O2 -g"
CGO_FFLAGS="-O2 -g"
CGO_LDFLAGS="-O2 -g"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build3394607480=/tmp/go-build -gno-record-gcc-switches"

git status (err=<nil>)
HEAD detached at 0b6a67ac4
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:32: run command via tools/syz-env for best compatibility, see:
Makefile:33: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' ./sys/syz-sysgen | grep -q false || go install ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=0b6a67ac4b0dc26f43030c5edd01c9175f13b784 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20230913-073137'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-fuzzer github.com/google/syzkaller/syz-fuzzer
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=0b6a67ac4b0dc26f43030c5edd01c9175f13b784 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20230913-073137'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
GOOS=linux GOARCH=amd64 go build "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=0b6a67ac4b0dc26f43030c5edd01c9175f13b784 -X 'github.com/google/syzkaller/prog.gitRevisionDate=20230913-073137'" "-tags=syz_target syz_os_linux syz_arch_amd64 " -o ./bin/linux_amd64/syz-stress github.com/google/syzkaller/tools/syz-stress
mkdir -p ./bin/linux_amd64
gcc -o ./bin/linux_amd64/syz-executor executor/executor.cc \
	-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -fpermissive -w -DGOOS_linux=1 -DGOARCH_amd64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"0b6a67ac4b0dc26f43030c5edd01c9175f13b784\"


Error text is too large and was truncated, full error text is at:
https://syzkaller.appspot.com/x/error.txt?x=137bc1b2680000


Tested on:

commit:         79be50b1 ima: annotate iint mutex to avoid lockdep fal..
git tree:       https://github.com/amir73il/linux ima-ovl-fix
kernel config:  https://syzkaller.appspot.com/x/.config?x=57da1ac039c4c78a
dashboard link: https://syzkaller.appspot.com/bug?extid=b42fe626038981fb7bfa
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.

Re: [syzbot] [integrity] [overlayfs] possible deadlock in mnt_want_write (2)

[Amir Goldstein]

On Thu, Oct 5, 2023 at 12:59 PM syzbot
<syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot tried to test the proposed patch but the build/boot failed:

My mistake. Please try again:

#syz test: https://github.com/amir73il/linux ima-ovl-fix

Re: [syzbot] [integrity] [overlayfs] possible deadlock in mnt_want_write (2)

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com

Tested on:

commit:         42555f30 ima: annotate iint mutex to avoid lockdep fal..
git tree:       https://github.com/amir73il/linux ima-ovl-fix
console output: https://syzkaller.appspot.com/x/log.txt?x=16889486680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=57da1ac039c4c78a
dashboard link: https://syzkaller.appspot.com/bug?extid=b42fe626038981fb7bfa
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Note: no patches were applied.
Note: testing is done by a robot and is best-effort only.

Re: [syzbot] [integrity] [overlayfs] possible deadlock in mnt_want_write (2)

[Mimi Zohar]

On Thu, 2023-10-05 at 13:26 +0300, Amir Goldstein wrote:
> On Thu, Oct 5, 2023 at 12:59 PM syzbot
> <syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com> wrote:
> >
> > Hello,
> >
> > syzbot tried to test the proposed patch but the build/boot failed:
> 
> My mistake. Please try again:
> 
> #syz test: https://github.com/amir73il/linux ima-ovl-fix

Thanks, Amir.   "mutext_init(&iint->mutex); moved, but the status
initialization lines 161-166 were dropped.   They're needed by IMA-
appraisal for signature verification.

        iint->ima_file_status = INTEGRITY_UNKNOWN;
	iint->ima_mmap_status = INTEGRITY_UNKNOWN;
	iint->ima_bprm_status = INTEGRITY_UNKNOWN;
	iint->ima_read_status = INTEGRITY_UNKNOWN;
	iint->ima_creds_status = INTEGRITY_UNKNOWN;
	iint->evm_status = INTEGRITY_UNKNOWN;

Re: [syzbot] [integrity] [overlayfs] possible deadlock in mnt_want_write (2)

[Amir Goldstein]

On Thu, Oct 5, 2023 at 4:14 PM Mimi Zohar <zohar@linux.ibm.com> wrote:
>
> On Thu, 2023-10-05 at 13:26 +0300, Amir Goldstein wrote:
> > On Thu, Oct 5, 2023 at 12:59 PM syzbot
> > <syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com> wrote:
> > >
> > > Hello,
> > >
> > > syzbot tried to test the proposed patch but the build/boot failed:
> >
> > My mistake. Please try again:
> >
> > #syz test: https://github.com/amir73il/linux ima-ovl-fix
>
> Thanks, Amir.   "mutext_init(&iint->mutex); moved, but the status
> initialization lines 161-166 were dropped.   They're needed by IMA-
> appraisal for signature verification.
>
>         iint->ima_file_status = INTEGRITY_UNKNOWN;
>         iint->ima_mmap_status = INTEGRITY_UNKNOWN;
>         iint->ima_bprm_status = INTEGRITY_UNKNOWN;
>         iint->ima_read_status = INTEGRITY_UNKNOWN;
>         iint->ima_creds_status = INTEGRITY_UNKNOWN;
>         iint->evm_status = INTEGRITY_UNKNOWN;
>

They are dropped from iint_init_once()
They are not needed there because there are now set
in every iint allocation in iint_init_always()
instead of being set in iint_free()

This is the standard practice for slab objects.
See inode_init_once()/inode_init_always().

Thanks,
Amir.

Re: [syzbot] [integrity] [overlayfs] possible deadlock in mnt_want_write (2)

[Mimi Zohar]

On Thu, 2023-10-05 at 16:22 +0300, Amir Goldstein wrote:
> On Thu, Oct 5, 2023 at 4:14 PM Mimi Zohar <zohar@linux.ibm.com> wrote:
> >
> > On Thu, 2023-10-05 at 13:26 +0300, Amir Goldstein wrote:
> > > On Thu, Oct 5, 2023 at 12:59 PM syzbot
> > > <syzbot+b42fe626038981fb7bfa@syzkaller.appspotmail.com> wrote:
> > > >
> > > > Hello,
> > > >
> > > > syzbot tried to test the proposed patch but the build/boot failed:
> > >
> > > My mistake. Please try again:
> > >
> > > #syz test: https://github.com/amir73il/linux ima-ovl-fix
> >
> > Thanks, Amir.   "mutext_init(&iint->mutex); moved, but the status
> > initialization lines 161-166 were dropped.   They're needed by IMA-
> > appraisal for signature verification.
> >
> >         iint->ima_file_status = INTEGRITY_UNKNOWN;
> >         iint->ima_mmap_status = INTEGRITY_UNKNOWN;
> >         iint->ima_bprm_status = INTEGRITY_UNKNOWN;
> >         iint->ima_read_status = INTEGRITY_UNKNOWN;
> >         iint->ima_creds_status = INTEGRITY_UNKNOWN;
> >         iint->evm_status = INTEGRITY_UNKNOWN;
> >
> 
> They are dropped from iint_init_once()
> They are not needed there because there are now set
> in every iint allocation in iint_init_always()
> instead of being set in iint_free()

I was only looking at the patch and noticed the removal.  Thanks, this
looks good.

Mimi