bisecting fixing commit since 9b15f7fae677336e04b9e026ff91854e43165455
building syzkaller on 1ce142dcc7e25341405592c66bcb7cb0d60d2b3a
testing commit 9b15f7fae677336e04b9e026ff91854e43165455 with gcc (GCC) 8.1.0
kernel signature: dd704c7e5805a40e7b4d185cf08b0edd98899c124694e7583fbf4d5313d9f009
all runs: crashed: WARNING in get_signal
testing current HEAD 93556fb211fa7f1e18f869bdce0c225c25594942
testing commit 93556fb211fa7f1e18f869bdce0c225c25594942 with gcc (GCC) 8.1.0
kernel signature: 90014c4b256c8d66f1546221c061e9ce78e71fe21ceb3f889e8df3a29a2a2767
all runs: crashed: WARNING in get_signal
revisions tested: 2, total time: 29m34.310054063s (build: 21m42.258497819s, test: 6m30.622252746s)
the crash still happens on HEAD
commit msg: Linux 4.19.111
crash: WARNING in get_signal
audit: type=1400 audit(1584612989.747:42): avc:  denied  { associate } for  pid=7441 comm="syz-executor.1" name="syz1" scontext=unconfined_u:object_r:unlabeled_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=filesystem permissive=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: 7625 at kernel/signal.c:2329 get_signal+0x13c9/0x1a00 include/linux/freezer.h:60
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 7625 Comm: syz-executor.0 Not tainted 4.19.111-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:1037
RIP: 0010:do_jobctl_trap kernel/signal.c:2329 [inline]
RIP: 0010:get_signal+0x13c9/0x1a00 kernel/signal.c:2462
Code: 31 db eb e1 48 89 df e8 65 31 16 00 84 c0 0f 84 c7 ed ff ff 31 ff e8 46 32 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 86 0a 15 00 84 c0 0f 85 15
RSP: 0018:ffff888084fe7c60 EFLAGS: 00010046
RAX: 00000001ffffffff RBX: ffff888084fe7dd8 RCX: ffffffff814bc4b0
RDX: 1ffff1100f707a83 RSI: 0000000000008000 RDI: ffff88808f4f17e0
RBP: ffff888084fe7d10 R08: ffffed100f707a82 R09: ffffed100f707a81
R10: ffffed100f707a81 R11: ffff88807b83d40b R12: ffff88808f4f1740
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff888084ed2100
 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:00007fe0eadccc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: 0000000000000000 RBX: 00007fe0eadcd6d4 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..