bisecting fixing commit since 9b15f7fae677336e04b9e026ff91854e43165455
building syzkaller on 1ce142dcc7e25341405592c66bcb7cb0d60d2b3a
testing commit 9b15f7fae677336e04b9e026ff91854e43165455 with gcc (GCC) 8.1.0
kernel signature: b9088574dce66987bbebbacaaa8bf5ccd0c09150f503774de3a904709cb74741
all runs: crashed: WARNING in get_signal
testing current HEAD 258f0cf7ac3b788a14c0d01aab3c4aea02f8c86e
testing commit 258f0cf7ac3b788a14c0d01aab3c4aea02f8c86e with gcc (GCC) 8.1.0
kernel signature: 1f5d6b8b23f6cf4ecb49976bf8d17031a7857f2346de6cde93b54cde46d95516
all runs: crashed: WARNING in get_signal
revisions tested: 2, total time: 26m52.420092712s (build: 19m24.626529903s, test: 6m9.088255437s)
the crash still happens on HEAD
commit msg: Linux 4.19.123
crash: WARNING in get_signal
IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready
batman_adv: batadv0: Interface activated: batadv_slave_1
IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
WARNING: CPU: 0 PID: 7869 at kernel/signal.c:2334 get_signal+0x13c9/0x1a00 include/linux/freezer.h:60
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 7869 Comm: syz-executor.0 Not tainted 4.19.123-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+0x123/0x177 lib/dump_stack.c:118
 panic+0x1cd/0x375 kernel/panic.c:186
 __warn.cold.8+0x1b/0x3e kernel/panic.c:541
 report_bug+0x1a4/0x200 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x200/0x350 arch/x86/kernel/traps.c:296
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:1038
RIP: 0010:do_jobctl_trap kernel/signal.c:2334 [inline]
RIP: 0010:get_signal+0x13c9/0x1a00 kernel/signal.c:2467
Code: 31 db eb e1 48 89 df e8 d5 2c 16 00 84 c0 0f 84 c7 ed ff ff 31 ff e8 b6 2d 16 00 e9 bb ed ff ff 41 89 c4 31 db e9 74 ff ff ff <0f> 0b be 00 80 00 00 e9 a9 f9 ff ff e8 f6 05 15 00 84 c0 0f 85 15
RSP: 0018:ffff888090cffc60 EFLAGS: 00010046
RAX: 00000001ffffffff RBX: ffff888090cffdd8 RCX: ffffffff814bdf90
RDX: 1ffff11015371a33 RSI: 0000000000008000 RDI: ffff88808c203420
RBP: ffff888090cffd10 R08: ffffed1015371a32 R09: ffffed1015371a31
R10: ffffed1015371a31 R11: ffff8880a9b8d18b R12: ffff88808c203380
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff88808c75e0c0
 do_signal+0x87/0x1960 arch/x86/kernel/signal.c:821
 exit_to_usermode_loop+0x114/0x200 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath+0x31a/0x3b0 arch/x86/entry/common.c:271
 ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:407
RIP: 0033:0x45c6b9
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fefe07f7c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: 0000000000000000 RBX: 00007fefe07f86d4 RCX: 000000000045c6b9
RDX: 9999999999999999 RSI: 0000000000000000 RDI: 000000000a01ffff
RBP: 000000000076bf20 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000074 R14: 00000000004c2f79 R15: 000000000076bf2c
Kernel Offset: disabled
Rebooting in 86400 seconds..