Hello,
syzbot found the following crash on:
HEAD commit: 556e2f60 Merge tag 'clk-fixes-for-linus' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=112a45a9a00000
kernel config: https://syzkaller.appspot.com/x/.config?x=9a31528e58cc12e2
dashboard link: https://syzkaller.appspot.com/bug?extid=002e636502bc4b64eb5c
compiler: clang version 9.0.0 (/home/glider/llvm/clang
80fee25776c2fb61e74c1ecb1a523375c2500b69)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1716d35ba00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1489f565a00000
The bug was bisected to:
commit 6fd2fe494b17bf2dec37b610d23a43a72b16923a
Author: Al Viro <[email protected]>
Date: Thu Jun 27 02:22:09 2019 +0000
copy_process(): don't use ksys_close() on cleanups
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=135a66f9a00000
final crash: https://syzkaller.appspot.com/x/report.txt?x=10da66f9a00000
console output: https://syzkaller.appspot.com/x/log.txt?x=175a66f9a00000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email protected]
Fixes: 6fd2fe494b17 ("copy_process(): don't use ksys_close() on cleanups")
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c
R13: 00007ffc15fbb0ff R14: 00007ff07e47e9c0 R15: 0000000000000000
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 7990 Comm: syz-executor290 Not tainted 5.2.0-rc6+ #9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline]
RIP: 0010:get_task_pid+0xe1/0x210 kernel/pid.c:372
Code: 89 ff e8 62 27 5f 00 49 8b 07 44 89 f1 4c 8d bc c8 90 01 00 00 eb 0c
e8 0d fe 25 00 49 81 c7 38 05 00 00 4c 89 f8 48 c1 e8 03 <80> 3c 18 00 74
08 4c 89 ff e8 31 27 5f 00 4d 8b 37 e8 f9 47 12 00
RSP: 0018:ffff88808a4a7d78 EFLAGS: 00010203
RAX: 00000000000000a7 RBX: dffffc0000000000 RCX: ffff888088180600
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88808a4a7d90 R08: ffffffff814fb3a8 R09: ffffed1015d66bf8
R10: ffffed1015d66bf8 R11: 1ffff11015d66bf7 R12: 0000000000041ffc
R13: 1ffff11011494fbc R14: 0000000000000000 R15: 000000000000053d
FS: 00007ff07e47e700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004b5100 CR3: 0000000094df2000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
_do_fork+0x1b9/0x5f0 kernel/fork.c:2360
__do_sys_clone kernel/fork.c:2454 [inline]
__se_sys_clone kernel/fork.c:2448 [inline]
__x64_sys_clone+0xc1/0xd0 kernel/fork.c:2448
do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:301
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x446649
Code: e8 bc b5 02 00 48 83 c4 18 c3 0f 1f 80 00 00 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 0f 83 2b 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ff07e47ddb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 0000000000446649
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000041ffc
RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c
R13: 00007ffc15fbb0ff R14: 00007ff07e47e9c0 R15: 0000000000000000
Modules linked in:
---[ end trace 403a74d6aeda7e67 ]---
RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline]
RIP: 0010:get_task_pid+0xe1/0x210 kernel/pid.c:372
Code: 89 ff e8 62 27 5f 00 49 8b 07 44 89 f1 4c 8d bc c8 90 01 00 00 eb 0c
e8 0d fe 25 00 49 81 c7 38 05 00 00 4c 89 f8 48 c1 e8 03 <80> 3c 18 00 74
08 4c 89 ff e8 31 27 5f 00 4d 8b 37 e8 f9 47 12 00
RSP: 0018:ffff88808a4a7d78 EFLAGS: 00010203
RAX: 00000000000000a7 RBX: dffffc0000000000 RCX: ffff888088180600
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88808a4a7d90 R08: ffffffff814fb3a8 R09: ffffed1015d66bf8
R10: ffffed1015d66bf8 R11: 1ffff11015d66bf7 R12: 0000000000041ffc
R13: 1ffff11011494fbc R14: 0000000000000000 R15: 000000000000053d
FS: 00007ff07e47e700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004b5100 CR3: 0000000094df2000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
---
This bug 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 [email protected].
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches
On Mon, Jul 01, 2019 at 06:17:06AM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: 556e2f60 Merge tag 'clk-fixes-for-linus' of git://git.kern..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=112a45a9a00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=9a31528e58cc12e2
> dashboard link: https://syzkaller.appspot.com/bug?extid=002e636502bc4b64eb5c
> compiler: clang version 9.0.0 (/home/glider/llvm/clang
> 80fee25776c2fb61e74c1ecb1a523375c2500b69)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1716d35ba00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1489f565a00000
>
> The bug was bisected to:
>
> commit 6fd2fe494b17bf2dec37b610d23a43a72b16923a
> Author: Al Viro <[email protected]>
> Date: Thu Jun 27 02:22:09 2019 +0000
>
> copy_process(): don't use ksys_close() on cleanups
I think I see the issue. Will hopefully have a fix in a bit.
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=135a66f9a00000
> final crash: https://syzkaller.appspot.com/x/report.txt?x=10da66f9a00000
> console output: https://syzkaller.appspot.com/x/log.txt?x=175a66f9a00000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: [email protected]
> Fixes: 6fd2fe494b17 ("copy_process(): don't use ksys_close() on cleanups")
>
> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c
> R13: 00007ffc15fbb0ff R14: 00007ff07e47e9c0 R15: 0000000000000000
> kasan: CONFIG_KASAN_INLINE enabled
> kasan: GPF could be caused by NULL-ptr deref or user memory access
> general protection fault: 0000 [#1] PREEMPT SMP KASAN
> CPU: 1 PID: 7990 Comm: syz-executor290 Not tainted 5.2.0-rc6+ #9
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline]
> RIP: 0010:get_task_pid+0xe1/0x210 kernel/pid.c:372
> Code: 89 ff e8 62 27 5f 00 49 8b 07 44 89 f1 4c 8d bc c8 90 01 00 00 eb 0c
> e8 0d fe 25 00 49 81 c7 38 05 00 00 4c 89 f8 48 c1 e8 03 <80> 3c 18 00 74 08
> 4c 89 ff e8 31 27 5f 00 4d 8b 37 e8 f9 47 12 00
> RSP: 0018:ffff88808a4a7d78 EFLAGS: 00010203
> RAX: 00000000000000a7 RBX: dffffc0000000000 RCX: ffff888088180600
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: ffff88808a4a7d90 R08: ffffffff814fb3a8 R09: ffffed1015d66bf8
> R10: ffffed1015d66bf8 R11: 1ffff11015d66bf7 R12: 0000000000041ffc
> R13: 1ffff11011494fbc R14: 0000000000000000 R15: 000000000000053d
> FS: 00007ff07e47e700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000004b5100 CR3: 0000000094df2000 CR4: 00000000001406e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> _do_fork+0x1b9/0x5f0 kernel/fork.c:2360
> __do_sys_clone kernel/fork.c:2454 [inline]
> __se_sys_clone kernel/fork.c:2448 [inline]
> __x64_sys_clone+0xc1/0xd0 kernel/fork.c:2448
> do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:301
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x446649
> Code: e8 bc b5 02 00 48 83 c4 18 c3 0f 1f 80 00 00 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
> 0f 83 2b 09 fc ff c3 66 2e 0f 1f 84 00 00 00 00
> RSP: 002b:00007ff07e47ddb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
> RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 0000000000446649
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000041ffc
> RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c
> R13: 00007ffc15fbb0ff R14: 00007ff07e47e9c0 R15: 0000000000000000
> Modules linked in:
> ---[ end trace 403a74d6aeda7e67 ]---
> RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline]
> RIP: 0010:get_task_pid+0xe1/0x210 kernel/pid.c:372
> Code: 89 ff e8 62 27 5f 00 49 8b 07 44 89 f1 4c 8d bc c8 90 01 00 00 eb 0c
> e8 0d fe 25 00 49 81 c7 38 05 00 00 4c 89 f8 48 c1 e8 03 <80> 3c 18 00 74 08
> 4c 89 ff e8 31 27 5f 00 4d 8b 37 e8 f9 47 12 00
> RSP: 0018:ffff88808a4a7d78 EFLAGS: 00010203
> RAX: 00000000000000a7 RBX: dffffc0000000000 RCX: ffff888088180600
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: ffff88808a4a7d90 R08: ffffffff814fb3a8 R09: ffffed1015d66bf8
> R10: ffffed1015d66bf8 R11: 1ffff11015d66bf7 R12: 0000000000041ffc
> R13: 1ffff11011494fbc R14: 0000000000000000 R15: 000000000000053d
> FS: 00007ff07e47e700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000004b5100 CR3: 0000000094df2000 CR4: 00000000001406e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
>
> ---
> This bug 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 [email protected].
>
> syzbot will keep track of this bug report. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> syzbot can test patches for this bug, for details see:
> https://goo.gl/tpsmEJ#testing-patches
Make sure to return a proper negative error code from copy_process()
when anon_inode_getfile() fails with CLONE_PIDFD.
Otherwise _do_fork() will not detect an error and get_task_pid() will
operator on a nonsensical pointer:
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c
R13: 00007ffc15fbb0ff R14: 00007ff07e47e9c0 R15: 0000000000000000
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 7990 Comm: syz-executor290 Not tainted 5.2.0-rc6+ #9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline]
RIP: 0010:get_task_pid+0xe1/0x210 kernel/pid.c:372
Code: 89 ff e8 62 27 5f 00 49 8b 07 44 89 f1 4c 8d bc c8 90 01 00 00 eb 0c
e8 0d fe 25 00 49 81 c7 38 05 00 00 4c 89 f8 48 c1 e8 03 <80> 3c 18 00 74
08 4c 89 ff e8 31 27 5f 00 4d 8b 37 e8 f9 47 12 00
RSP: 0018:ffff88808a4a7d78 EFLAGS: 00010203
RAX: 00000000000000a7 RBX: dffffc0000000000 RCX: ffff888088180600
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88808a4a7d90 R08: ffffffff814fb3a8 R09: ffffed1015d66bf8
R10: ffffed1015d66bf8 R11: 1ffff11015d66bf7 R12: 0000000000041ffc
R13: 1ffff11011494fbc R14: 0000000000000000 R15: 000000000000053d
FS: 00007ff07e47e700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004b5100 CR3: 0000000094df2000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
_do_fork+0x1b9/0x5f0 kernel/fork.c:2360
__do_sys_clone kernel/fork.c:2454 [inline]
__se_sys_clone kernel/fork.c:2448 [inline]
__x64_sys_clone+0xc1/0xd0 kernel/fork.c:2448
do_syscall_64+0xfe/0x140 arch/x86/entry/common.c:301
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Link: https://lore.kernel.org/lkml/[email protected]
Reported-and-tested-by: [email protected]
Fixes: 6fd2fe494b17 ("copy_process(): don't use ksys_close() on cleanups")
Cc: Jann Horn <[email protected]>
Cc: Al Viro <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>
---
kernel/fork.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/fork.c b/kernel/fork.c
index 61667909ce83..fe83343da24b 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2036,6 +2036,7 @@ static __latent_entropy struct task_struct *copy_process(
O_RDWR | O_CLOEXEC);
if (IS_ERR(pidfile)) {
put_unused_fd(pidfd);
+ retval = PTR_ERR(pidfile);
goto bad_fork_free_pid;
}
get_pid(pid); /* held by pidfile now */
--
2.22.0
Hi Linus,
This contains a single urgent fix for copy_process() in kernel/fork.c:
The following changes since commit 6fbc7275c7a9ba97877050335f290341a1fd8dbf:
Linux 5.2-rc7 (2019-06-30 11:25:36 +0800)
are available in the Git repository at:
[email protected]:pub/scm/linux/kernel/git/brauner/linux tags/for-linus-20190701
for you to fetch changes up to 28dd29c06d0dede4b32b2c559cff21955a830928:
fork: return proper negative error code (2019-07-01 16:43:30 +0200)
With Al's removal of ksys_close() from cleanup paths in copy_process() a
bug was introduced. When anon_inode_getfile() failed the cleanup was
correctly performed but the error code was not propagated to callers of
copy_process() causing them to operate on a nonsensical pointer. The fix is
a simple on-liner which makes sure that a proper negative error code is
returned from copy_process().
syzkaller has also verified that the bug is not reproducible with the patch
in this branch.
Please consider pulling these changes from the signed for-linus-20190701 tag.
Thanks!
Christian
----------------------------------------------------------------
for-linus-20190701
----------------------------------------------------------------
Christian Brauner (1):
fork: return proper negative error code
kernel/fork.c | 1 +
1 file changed, 1 insertion(+)
On Mon, Jul 01, 2019 at 04:48:08PM +0200, Christian Brauner wrote:
> Make sure to return a proper negative error code from copy_process()
> when anon_inode_getfile() fails with CLONE_PIDFD.
Acked-by: Al Viro <[email protected]>
The pull request you sent on Mon, 1 Jul 2019 18:15:03 +0200:
> [email protected]:pub/scm/linux/kernel/git/brauner/linux tags/for-linus-20190701
has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/8d68d93255227da660c63b9162f7001e2f5d470a
Thank you!
--
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