general protection fault in put_pid

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: bab5c80b2110 Merge tag 'armsoc-fixes-4.19' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=109ecf6e400000
kernel config: https://syzkaller.appspot.com/x/.config?x=88e9a8a39dc0be2d
dashboard link: https://syzkaller.appspot.com/bug?extid=9e9a6927da1150ac12df
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
CC: [ak...@linux-foundation.org dhow...@redhat.com
ebie...@xmission.com gs05...@gmail.com linux-...@vger.kernel.org
mawi...@microsoft.com ol...@redhat.com ri...@redhat.com
rp...@linux.vnet.ibm.com]

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+9e9a69...@syzkaller.appspotmail.com

x_tables: eb_tables: snat target: used from hooks PREROUTING, but only
usable from POSTROUTING
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: 10388 Comm: syz-executor1 Not tainted 4.19.0-rc7+ #281
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:put_pid.part.2+0xb6/0x240 kernel/pid.c:108
kobject: 'loop3' (00000000a88c2f60): kobject_uevent_env
Code: d2 0f 85 89 01 00 00 44 8b 63 04 49 8d 44 24 03 48 c1 e0 04 48 8d 7c
03 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 66 01 00 00 49 83 c4 03 be 04 00 00 00 48 89 df
kobject: 'loop3' (00000000a88c2f60): fill_kobj_path: path
= '/devices/virtual/block/loop3'
RSP: 0018:ffff8801c5def1f0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffffffff816070d0 RCX: ffffffff8339697e
RDX: 00000001933e9062 RSI: ffffffff8152688e RDI: 0000000c99f48310
RBP: ffff8801c5def280 R08: ffff88018456c640 R09: fffff5200272c200
R10: fffff5200272c200 R11: ffffc90013961003 R12: 00000000d1894120
R13: 1ffff10038bbde3f R14: ffff8801c5def258 R15: dffffc0000000000
FS: 00000000025cc940(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000619570 CR3: 00000001af510000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
put_pid+0x1f/0x30 kernel/pid.c:105
ipc_update_pid ipc/util.h:159 [inline]
freeary+0x10c8/0x1a40 ipc/sem.c:1167
free_ipcs+0x9f/0x1c0 ipc/namespace.c:112
sem_exit_ns+0x20/0x40 ipc/sem.c:237
free_ipc_ns ipc/namespace.c:120 [inline]
put_ipc_ns+0x66/0x180 ipc/namespace.c:152
free_nsproxy+0xcf/0x220 kernel/nsproxy.c:180
switch_task_namespaces+0xb3/0xd0 kernel/nsproxy.c:229
exit_task_namespaces+0x17/0x20 kernel/nsproxy.c:234
do_exit+0x1ad2/0x2610 kernel/exit.c:866
do_group_exit+0x177/0x440 kernel/exit.c:970
__do_sys_exit_group kernel/exit.c:981 [inline]
__se_sys_exit_group kernel/exit.c:979 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:979
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457569
Code: Bad RIP value.
RSP: 002b:0000000000a3fc88 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000457569
RDX: 0000000000410f40 RSI: 0000000000a44bf0 RDI: 0000000000000045
RBP: 00000000004bcf74 R08: 000000000000000c R09: 0000000000000000
R10: 00000000025cc940 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000000173 R15: 0000000000000001
Modules linked in:
---[ end trace dca4f33c5c905129 ]---
RIP: 0010:put_pid.part.2+0xb6/0x240 kernel/pid.c:108
Code: d2 0f 85 89 01 00 00 44 8b 63 04 49 8d 44 24 03 48 c1 e0 04 48 8d 7c
03 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 66 01 00 00 49 83 c4 03 be 04 00 00 00 48 89 df
IPVS: ftp: loaded support on port[0] = 21
RSP: 0018:ffff8801c5def1f0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffffffff816070d0 RCX: ffffffff8339697e
kobject: 'loop4' (00000000baef0bd9): kobject_uevent_env
RDX: 00000001933e9062 RSI: ffffffff8152688e RDI: 0000000c99f48310
RBP: ffff8801c5def280 R08: ffff88018456c640 R09: fffff5200272c200
kobject: 'loop4' (00000000baef0bd9): fill_kobj_path: path
= '/devices/virtual/block/loop4'
R10: fffff5200272c200 R11: ffffc90013961003 R12: 00000000d1894120
R13: 1ffff10038bbde3f R14: ffff8801c5def258 R15: dffffc0000000000
FS: 00000000025cc940(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
kobject: 'lo' (00000000bc1eaed5): kobject_add_internal: parent: 'net',
set: 'devices'
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
kobject: 'lo' (00000000bc1eaed5): kobject_uevent_env
CR2: 000000000045753f CR3: 000000000926a000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
kobject: 'loop5' (000000007f7f04e6): kobject_uevent_env


---
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[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: f5d582777bcb Merge branch 'for-linus' of git://git.kernel...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=135bc547400000
kernel config: https://syzkaller.appspot.com/x/.config?x=c8970c89a0efbb23

dashboard link: https://syzkaller.appspot.com/bug?extid=9e9a6927da1150ac12df
compiler: gcc (GCC) 8.0.1 20180413 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16803afb400000
CC: [ak...@linux-foundation.org dhow...@redhat.com
ebie...@xmission.com ktsana...@zendesk.com
linux-...@vger.kernel.org mho...@suse.com rp...@linux.vnet.ibm.com
s...@canb.auug.org.au wi...@infradead.org]

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+9e9a69...@syzkaller.appspotmail.com

kmem_cache 221KB 225KB
Out of memory: Kill process 6139 (syz-execprog) score 1 or sacrifice child
Killed process 6164 (syz-executor0) total-vm:37444kB, anon-rss:60kB,
file-rss:0kB, shmem-rss:0kB
oom_reaper: reaped process 6164 (syz-executor0), now anon-rss:0kB,
file-rss:0kB, shmem-rss:0kB

kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN

CPU: 0 PID: 6159 Comm: syz-executor3 Not tainted 4.20.0-rc6+ #151

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011

RIP: 0010:put_pid.part.3+0xb6/0x240 kernel/pid.c:108

Code: d2 0f 85 89 01 00 00 44 8b 63 04 49 8d 44 24 03 48 c1 e0 04 48 8d 7c
03 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 66 01 00 00 49 83 c4 03 be 04 00 00 00 48 89 df

RSP: 0018:ffff8881ae116e78 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffffffff816149a0 RCX: ffffffff833e420e
RDX: 00000001933eab7c RSI: ffffffff8152bf8e RDI: 0000000c99f55be0
RBP: ffff8881ae116f08 R08: ffff8881cdbf2300 R09: fffff52001507600
R10: fffff52001507600 R11: ffffc9000a83b003 R12: 00000000d1894120
R13: 1ffff11035c22dd0 R14: ffff8881ae116ee0 R15: dffffc0000000000
FS: 000000000166d940(0000) GS:ffff8881dae00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 000000000075c458 CR3: 00000001d2bd1000 CR4: 00000000001406f0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
put_pid+0x1f/0x30 kernel/pid.c:105
ipc_update_pid ipc/util.h:159 [inline]
freeary+0x10c8/0x1a40 ipc/sem.c:1167
free_ipcs+0x9f/0x1c0 ipc/namespace.c:112
sem_exit_ns+0x20/0x40 ipc/sem.c:237
free_ipc_ns ipc/namespace.c:120 [inline]
put_ipc_ns+0x66/0x180 ipc/namespace.c:152
free_nsproxy+0xcf/0x220 kernel/nsproxy.c:180
switch_task_namespaces+0xb3/0xd0 kernel/nsproxy.c:229
exit_task_namespaces+0x17/0x20 kernel/nsproxy.c:234

do_exit+0x1ad1/0x26d0 kernel/exit.c:866
do_group_exit+0x177/0x440 kernel/exit.c:970
get_signal+0x8b0/0x1980 kernel/signal.c:2517
do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816
exit_to_usermode_loop+0x2e5/0x380 arch/x86/entry/common.c:162
prepare_exit_to_usermode+0x342/0x3b0 arch/x86/entry/common.c:197
retint_user+0x8/0x18
RIP: 0033:0x45a4d0
Code: 10 44 00 00 00 e8 c0 cc ff ff 0f b6 44 24 18 eb c2 e8 44 ad ff ff e9
6f ff ff ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc <64> 48 8b 0c 25
f8 ff ff ff 48 3b 61 10 76 68 48 83 ec 28 48 89 6c
RSP: 002b:00007fff9b9d3578 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000000000a4edb RCX: 0000000000483170
RDX: 0000000000000000 RSI: 00007fff9b9d3580 RDI: 0000000000000001
RBP: 00000000000002ef R08: 0000000000000001 R09: 000000000166d940
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00000000000a4e70 R14: 00000000000001f1 R15: 0000000000000003
Modules linked in:
---[ end trace 9933854824df8420 ]---
RIP: 0010:put_pid.part.3+0xb6/0x240 kernel/pid.c:108

Code: d2 0f 85 89 01 00 00 44 8b 63 04 49 8d 44 24 03 48 c1 e0 04 48 8d 7c
03 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f
85 66 01 00 00 49 83 c4 03 be 04 00 00 00 48 89 df

RSP: 0018:ffff8881ae116e78 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffffffff816149a0 RCX: ffffffff833e420e
RDX: 00000001933eab7c RSI: ffffffff8152bf8e RDI: 0000000c99f55be0
RBP: ffff8881ae116f08 R08: ffff8881cdbf2300 R09: fffff52001507600
R10: fffff52001507600 R11: ffffc9000a83b003 R12: 00000000d1894120
R13: 1ffff11035c22dd0 R14: ffff8881ae116ee0 R15: dffffc0000000000
FS: 000000000166d940(0000) GS:ffff8881dae00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 000000000075c458 CR3: 00000001d2bd1000 CR4: 00000000001406f0

[Dmitry Vyukov]

#syz upstream

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