WARNING in ovl_real_fdget_meta

From: syzbot
Date: Wed Jul 24 2019 - 15:18:27 EST


syzbot found the following crash on:

HEAD commit: c6dd78fc Merge branch 'x86-urgent-for-linus' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1346d53fa00000
kernel config: https://syzkaller.appspot.com/x/.config?x=3c8985c08e1f9727
dashboard link: https://syzkaller.appspot.com/bug?extid=032bc63605089a199d30
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15855334600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17fcc4c8600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+032bc63605089a199d30@xxxxxxxxxxxxxxxxxxxxxxxxx

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WARNING: CPU: 1 PID: 8471 at fs/overlayfs/file.c:55 ovl_change_flags fs/overlayfs/file.c:55 [inline]
WARNING: CPU: 1 PID: 8471 at fs/overlayfs/file.c:55 ovl_real_fdget_meta.cold+0x11/0x1e fs/overlayfs/file.c:106
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 8471 Comm: syz-executor111 Not tainted 5.2.0+ #71
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x16f/0x1f0 lib/dump_stack.c:113
panic+0x2dc/0x755 kernel/panic.c:219
__warn.cold+0x20/0x4c kernel/panic.c:576
report_bug+0x263/0x2b0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:179 [inline]
fixup_bug arch/x86/kernel/traps.c:174 [inline]
do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291
invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1026
RIP: 0010:ovl_change_flags fs/overlayfs/file.c:55 [inline]
RIP: 0010:ovl_real_fdget_meta.cold+0x11/0x1e fs/overlayfs/file.c:106
Code: e9 b3 fd ff ff e8 0c 68 4f ff e9 fb fd ff ff e8 02 68 4f ff e9 15 fe ff ff e8 b8 a6 15 ff 48 c7 c7 a0 45 b3 87 e8 c0 db ff fe <0f> 0b 41 bc fb ff ff ff e9 68 c6 ff ff e8 9a a6 15 ff 48 c7 c7 a0
RSP: 0018:ffff8880a1bffdc0 EFLAGS: 00010286
RAX: 0000000000000024 RBX: 0000000004048000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815b9de2 RDI: ffffed101437ffaa
RBP: ffff8880a1bffdf0 R08: 0000000000000024 R09: ffffed1015d26079
R10: ffffed1015d26078 R11: ffff8880ae9303c7 R12: 000000000000a000
R13: ffff88809bc592c0 R14: ffff88809bc59338 R15: ffff8880898e0460
ovl_real_fdget fs/overlayfs/file.c:113 [inline]
ovl_llseek+0x105/0x3b0 fs/overlayfs/file.c:163
vfs_llseek fs/read_write.c:300 [inline]
ksys_lseek+0x116/0x1b0 fs/read_write.c:313
__do_sys_lseek fs/read_write.c:324 [inline]
__se_sys_lseek fs/read_write.c:322 [inline]
__x64_sys_lseek+0x73/0xb0 fs/read_write.c:322
do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
RIP: 0033:0x441ce9
Code: e8 1c b4 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 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffcff68e398 EFLAGS: 00000246 ORIG_RAX: 0000000000000008
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441ce9
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000402af0 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..

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