bisecting fixing commit since 3c8c23092588a23bf1856a64f58c37f477a413be
building syzkaller on 8bdd5343e64460868dd1318257a39f1e7fd89471
testing commit 3c8c23092588a23bf1856a64f58c37f477a413be
compiler: gcc version 8.4.1 20210217 (GCC)
kernel signature: 19b3a33927a5181e82ecb9629199c058edc3e27a2eaf85006f468c3a5f1da806
all runs: crashed: WARNING in __writeback_inodes_sb_nr
testing current HEAD 2950c9c5e0df6bd34af45a5168bbee345e95eae2
testing commit 2950c9c5e0df6bd34af45a5168bbee345e95eae2
compiler: gcc version 8.4.1 20210217 (GCC)
kernel signature: 55a792ddae98aad56332b64899dc361f20995bab7f6416906c446307a71b1249
all runs: crashed: WARNING in __writeback_inodes_sb_nr
revisions tested: 2, total time: 27m27.293761887s (build: 19m59.96943313s, test: 7m1.582634833s)
the crash still happens on HEAD
commit msg: Linux 4.19.207
crash: WARNING in __writeback_inodes_sb_nr
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
IPv6: ADDRCONF(NETDEV_UP): wlan1: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready
------------[ cut here ]------------
wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
WARNING: CPU: 0 PID: 9936 at fs/fs-writeback.c:2370 __writeback_inodes_sb_nr.cold.13+0xc/0x13 fs/fs-writeback.c:2370
wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 9936 Comm: btrfs-transacti Not tainted 4.19.207-syzkaller #0
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+0x17c/0x226 lib/dump_stack.c:118
IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
 panic+0x1cd/0x375 kernel/panic.c:186
 __warn.cold.7+0x1b/0x36 kernel/panic.c:541
IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready
 report_bug+0x1a1/0x200 lib/bug.c:183
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 fixup_bug arch/x86/kernel/traps.c:173 [inline]
 do_error_trap+0x200/0x350 arch/x86/kernel/traps.c:296
wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038
RIP: 0010:__writeback_inodes_sb_nr.cold.13+0xc/0x13 fs/fs-writeback.c:2370
Code: ae 48 89 df e8 87 b8 07 fa eb e2 48 c7 c7 c0 dc 13 88 e8 a9 00 ff ff 0f 0b e9 12 f9 1a fa 48 c7 c7 c0 dc 13 88 e8 96 00 ff ff <0f> 0b e9 e5 1f 1b fa 48 c7 c7 c0 dc 13 88 e8 83 00 ff ff 0f 0b e9
RSP: 0018:ffff88809ecb7c38 EFLAGS: 00010282
RAX: 0000000000000024 RBX: 1ffff11013d96f89 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff885024a0 RDI: ffffffff8bad9720
RBP: ffff88809ecb7d30 R08: ffffed1017444ea9 R09: ffffed1017444ea8
R10: ffffed1017444ea8 R11: ffff8880ba227547 R12: ffff8880983c2b00
R13: ffff888097cc4c30 R14: ffff88809ecb7c68 R15: ffff888097cc4b00
ieee80211 phy13: Selected rate control algorithm 'minstrel_ht'
 writeback_inodes_sb_nr fs/fs-writeback.c:2390 [inline]
 writeback_inodes_sb+0x22/0x30 fs/fs-writeback.c:2405
 btrfs_start_delalloc_flush fs/btrfs/transaction.c:1927 [inline]
 btrfs_commit_transaction+0x1974/0x2330 fs/btrfs/transaction.c:2078
 transaction_kthread+0x2a2/0x380 fs/btrfs/disk-io.c:1794
 kthread+0x347/0x410 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Kernel Offset: disabled
Rebooting in 86400 seconds..