syzbot

------------[ cut here ]------------
WARNING: CPU: 0 PID: 11659 at fs/buffer.c:640 __set_page_dirty.constprop.0+0x14c/0x1c0 fs/buffer.c:640()
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 11659 Comm: syz-executor.0 Not tainted 4.4.174+ #4
 0000000000000000 ceefd1222f789d52 ffff880093b37540 ffffffff81aad1a1
 0000000000000000 ffffffff82835ee0 ffffffff828a31c0 0000000000000280
 ffffffff8154387c ffff880093b37620 ffffffff813a48c2 0000000041b58ab3
Call Trace:
 [<ffffffff81aad1a1>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81aad1a1>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<ffffffff813a48c2>] panic+0x1b9/0x37b kernel/panic.c:112
 [<ffffffff813a4ab9>] warn_slowpath_common kernel/panic.c:455 [inline]
 [<ffffffff813a4ab9>] warn_slowpath_common.cold+0x20/0x20 kernel/panic.c:435
 [<ffffffff810d3aaa>] warn_slowpath_null+0x2a/0x30 kernel/panic.c:492
 [<ffffffff8154387c>] __set_page_dirty.constprop.0+0x14c/0x1c0 fs/buffer.c:640
 [<ffffffff81544cb8>] __set_page_dirty_buffers+0x108/0x1b0 fs/buffer.c:701
 [<ffffffff813d426c>] set_page_dirty+0xbc/0x150 mm/page-writeback.c:2564
 [<ffffffff81547e2f>] block_page_mkwrite+0x1df/0x270 fs/buffer.c:2455
 [<ffffffff81665af0>] ext4_page_mkwrite+0xb80/0xef0 fs/ext4/inode.c:5483
 [<ffffffff8142eb82>] do_page_mkwrite+0x1d2/0x360 mm/memory.c:2057
 [<ffffffff814344fc>] wp_page_shared mm/memory.c:2327 [inline]
 [<ffffffff814344fc>] do_wp_page+0xb5c/0x1340 mm/memory.c:2431
 [<ffffffff8143b2e4>] handle_pte_fault mm/memory.c:3362 [inline]
 [<ffffffff8143b2e4>] __handle_mm_fault mm/memory.c:3474 [inline]
 [<ffffffff8143b2e4>] handle_mm_fault+0x1614/0x3140 mm/memory.c:3503
 [<ffffffff810aaa4e>] __do_page_fault+0x28e/0x7f0 arch/x86/mm/fault.c:1243
 [<ffffffff810ab008>] do_page_fault+0x28/0x30 arch/x86/mm/fault.c:1306
 [<ffffffff82719e35>] page_fault+0x25/0x30 arch/x86/entry/entry_64.S:1064
 [<ffffffff821dd4c5>] SYSC_sendmmsg net/socket.c:2090 [inline]
 [<ffffffff821dd4c5>] SyS_sendmmsg+0x35/0x60 net/socket.c:2085
 [<ffffffff82718ba1>] entry_SYSCALL_64_fastpath+0x1e/0x9a
Kernel Offset: disabled
Rebooting in 86400 seconds..