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Message-ID: <CACT4Y+YpBv-nRZsZmP674kU1e8V4Qt71hcfWXu-ZF80xxidDmQ@mail.gmail.com>
Date: Wed, 23 Dec 2015 11:37:39 +0100
From: Dmitry Vyukov <dvyukov@...gle.com>
To: Jeff Layton <jlayton@...chiereds.net>,
"J. Bruce Fields" <bfields@...ldses.org>,
Alexander Viro <viro@...iv.linux.org.uk>,
"linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>
Cc: syzkaller <syzkaller@...glegroups.com>,
Kostya Serebryany <kcc@...gle.com>,
Alexander Potapenko <glider@...gle.com>,
Sasha Levin <sasha.levin@...cle.com>,
Eric Dumazet <edumazet@...gle.com>
Subject: fs: WARNING in locks_free_lock_context()
Hello,
The following program triggers
WARN_ON_ONCE(!list_empty(&ctx->flc_posix)) warning in
locks_free_lock_context (run it in a loop):
// autogenerated by syzkaller (http://github.com/google/syzkaller)
#include <unistd.h>
#include <sys/syscall.h>
#include <string.h>
#include <stdint.h>
#include <pthread.h>
#ifndef SYS_memfd_create
#define SYS_memfd_create 319
#endif
long r[15];
long done[14];
void *thr(void *arg)
{
if (rand()%2)
usleep(100);
switch ((long)arg) {
case 0:
r[0] = syscall(SYS_mmap, 0x20000000ul, 0x5000ul,
0x3ul, 0x32ul, 0xfffffffffffffffful, 0x0ul);
break;
case 1:
memcpy((void*)0x20000c49,
"\xb6\x70\x70\x70\x31\x73\x65\x63\x75\x72\x69\x74\x79\x9e\x00", 15);
r[2] = syscall(SYS_memfd_create, 0x20000c49ul, 0x3ul,
0, 0, 0, 0);
break;
case 2:
r[3] = syscall(SYS_socketpair, 0x1ul, 0x1ul, 0x0ul,
0x20001000ul, 0, 0);
if (r[3] != -1)
r[4] = *(uint32_t*)0x20001000;
if (r[3] != -1)
r[5] = *(uint32_t*)0x20001004;
break;
case 3:
*(uint16_t*)0x20000000 = (uint16_t)0x0;
*(uint16_t*)0x20000002 = (uint16_t)0x1;
*(uint64_t*)0x20000008 = (uint64_t)0x6;
*(uint64_t*)0x20000010 = (uint64_t)0xad;
*(uint32_t*)0x20000018 = (uint32_t)0x0;
r[11] = syscall(SYS_fcntl, r[5], 0x7ul, 0x20000000ul, 0, 0, 0);
break;
case 4:
r[12] = syscall(SYS_write, r[5], 0x200006cbul,
0x1000ul, 0, 0, 0);
break;
case 5:
r[13] = syscall(SYS_close, r[5], 0, 0, 0, 0, 0);
break;
case 6:
r[14] = syscall(SYS_dup2, r[2], r[4], 0, 0, 0, 0);
break;
}
done[(long)arg] = 1;
return 0;
}
int main()
{
long i, j;
pthread_t th[14];
srand(time(0)+getpid());
memset(r, -1, sizeof(r));
for (i = 0; i < 7; i++) {
pthread_create(&th[i], 0, thr, (void*)i);
for (j = 0; j < 10; j++) {
if (done[i])
break;
usleep(100);
}
}
for (i = 0; i < 7; i++)
done[i] = 0;
for (i = 0; i < 7; i++) {
pthread_create(&th[7+i], 0, thr, (void*)i);
if (rand()%2)
continue;
for (j = 0; j < 10; j++) {
if (done[i])
break;
usleep(100);
}
}
usleep(100);
return 0;
}
------------[ cut here ]------------
WARNING: CPU: 3 PID: 1975 at fs/locks.c:241
locks_free_lock_context+0x118/0x180()
Modules linked in:
CPU: 3 PID: 1975 Comm: a.out Not tainted 4.4.0-rc6+ #173
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
00000000ffffffff ffff880068e67bf8 ffffffff82899ffd 0000000000000000
ffff88006130af00 ffffffff85e17d60 ffff880068e67c38 ffffffff812ebbb9
ffffffff818162d8 ffffffff85e17d60 00000000000000f1 ffff8800685c2828
Call Trace:
[< inline >] __dump_stack lib/dump_stack.c:15
[<ffffffff82899ffd>] dump_stack+0x6f/0xa2 lib/dump_stack.c:50
[<ffffffff812ebbb9>] warn_slowpath_common+0xd9/0x140 kernel/panic.c:460
[<ffffffff812ebde9>] warn_slowpath_null+0x29/0x30 kernel/panic.c:493
[<ffffffff818162d8>] locks_free_lock_context+0x118/0x180 fs/locks.c:241
[<ffffffff81765783>] __destroy_inode+0x1d3/0x4d0 fs/inode.c:228
[<ffffffff81765acb>] destroy_inode+0x4b/0x120 fs/inode.c:253
[<ffffffff81765ec0>] evict+0x320/0x4f0 fs/inode.c:559
[< inline >] iput_final fs/inode.c:1477
[<ffffffff817665dc>] iput+0x45c/0x850 fs/inode.c:1504
[< inline >] dentry_iput fs/dcache.c:358
[<ffffffff81757237>] __dentry_kill+0x457/0x620 fs/dcache.c:543
[< inline >] dentry_kill fs/dcache.c:587
[<ffffffff8175c499>] dput+0x659/0x740 fs/dcache.c:796
[<ffffffff817162fc>] __fput+0x42c/0x780 fs/file_table.c:226
[<ffffffff817166d5>] ____fput+0x15/0x20 fs/file_table.c:244
[<ffffffff8134679b>] task_work_run+0x16b/0x200 kernel/task_work.c:115
[< inline >] tracehook_notify_resume include/linux/tracehook.h:191
[<ffffffff81003990>] exit_to_usermode_loop+0x180/0x1a0
arch/x86/entry/common.c:251
[< inline >] prepare_exit_to_usermode arch/x86/entry/common.c:282
[<ffffffff8100631f>] syscall_return_slowpath+0x19f/0x210
arch/x86/entry/common.c:344
[<ffffffff85ccea22>] int_ret_from_sys_call+0x25/0x9f
arch/x86/entry/entry_64.S:281
---[ end trace 2dde0624dd974a19 ]---
On commit 4ef7675344d687a0ef5b0d7c0cee12da005870c0 (Dec 20).
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