syzbot

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current->flags & PF_MEMALLOC
WARNING: fs/ext4/inode.c:5764 at ext4_write_inode+0x544/0x620 fs/ext4/inode.c:5764, CPU#0: kswapd0/75
Modules linked in:
CPU: 0 UID: 0 PID: 75 Comm: kswapd0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:ext4_write_inode+0x544/0x620 fs/ext4/inode.c:5764
Code: 8b 05 90 55 af 10 48 3b 44 24 30 75 5a 44 89 e0 48 83 c4 38 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 5d 2b 3c ff 90 <0f> 0b 90 eb cf e8 52 2b 3c ff 41 bc fb ff ff ff eb c2 e8 45 2b 3c
RSP: 0018:ffffc90000acee80 EFLAGS: 00010293
RAX: ffffffff82899ab3 RBX: 0000000000000800 RCX: ffff888000d04a80
RDX: 0000000000000000 RSI: 0000000000000800 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffffffff90304ff7 R09: 1ffffffff20609fe
R10: dffffc0000000000 R11: ffffffff82899570 R12: 0000000000000000
R13: ffffc90000acefc0 R14: ffff888013370b90 R15: ffff888000d04a80
FS:  0000000000000000(0000) GS:ffff88808c891000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f90327d3e18 CR3: 000000000bb3a000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 write_inode fs/fs-writeback.c:1584 [inline]
 __writeback_single_inode+0x75a/0x10e0 fs/fs-writeback.c:1827
 writeback_single_inode+0x4ac/0xdc0 fs/fs-writeback.c:1883
 write_inode_now+0x1c2/0x290 fs/fs-writeback.c:2974
 iput_final fs/inode.c:1950 [inline]
 iput+0x8c1/0xe80 fs/inode.c:2009
 __dentry_kill+0x1a2/0x690 fs/dcache.c:718
 shrink_kill+0xa9/0x2c0 fs/dcache.c:1195
 shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1222
 prune_dcache_sb+0x119/0x180 fs/dcache.c:1304
 super_cache_scan+0x369/0x4b0 fs/super.c:223
 do_shrink_slab+0x6fb/0x1150 mm/shrinker.c:436
 shrink_slab_memcg mm/shrinker.c:553 [inline]
 shrink_slab+0x835/0x11f0 mm/shrinker.c:631
 shrink_one+0x2d9/0x710 mm/vmscan.c:5071
 shrink_many mm/vmscan.c:5132 [inline]
 lru_gen_shrink_node mm/vmscan.c:5210 [inline]
 shrink_node+0x31bf/0x3ae0 mm/vmscan.c:6198
 kswapd_shrink_node mm/vmscan.c:7052 [inline]
 balance_pgdat mm/vmscan.c:7228 [inline]
 kswapd+0x1736/0x2de0 mm/vmscan.c:7501
 kthread+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>