bisecting fixing commit since 768292d053619b2725b846ed2bf556bf40f43de2
building syzkaller on 3f4e812b87c43b6cdc98b4d66673f6575d63d4fb
testing commit 768292d053619b2725b846ed2bf556bf40f43de2 with gcc (GCC) 8.1.0
kernel signature: a7a921efda645c7113e7b9afa878683e32794787
all runs: crashed: WARNING in get_signal
testing current HEAD dcd888983542055210f5e68f1b1f1f8fe11a369a
testing commit dcd888983542055210f5e68f1b1f1f8fe11a369a with gcc (GCC) 8.1.0
kernel signature: 75ed42b482093076d8f47bbcbb9112460f42968b
all runs: crashed: WARNING in get_signal
revisions tested: 2, total time: 24m6.303572488s (build: 16m48.228586392s, test: 6m33.477697363s)
the crash still happens on HEAD
commit msg: Linux 4.19.95
crash: WARNING in get_signal
IPv6: ADDRCONF(NETDEV_UP): veth1_to_hsr: link is not ready
IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready
8021q: adding VLAN 0 to HW filter on device batadv0
IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_hsr: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready
WARNING: CPU: 1 PID: 7059 at kernel/signal.c:2324 get_signal+0x13c9/0x1a00 include/linux/freezer.h:60
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 7059 Comm: syz-executor.0 Not tainted 4.19.95-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:2324 [inline]
RIP: 0010:get_signal+0x13c9/0x1a00 kernel/signal.c:2457
Code: 31 db eb e1 48 89 df e8 05 20 16 00 84 c0 0f 84 c7 ed ff ff 31 ff e8 e6 20 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 76 f9 14 00 84 c0 0f 85 15
RSP: 0018:ffff888088d87c60 EFLAGS: 00010046
RAX: 00000001ffffffff RBX: ffff888088d87dd8 RCX: ffffffff814c9980
RDX: 1ffff1101255ef5b RSI: 0000000000008000 RDI: ffff888092851220
RBP: ffff888088d87d10 R08: ffffed101255ef5a R09: ffffed101255ef59
R10: ffffed101255ef59 R11: ffff888092af7acb R12: ffff888092851180
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff88807d1e4380
 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: 0033:0x4592c9
Code: fd b7 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fae2eb92c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 00000000004592c9
RDX: 9999999999999999 RSI: 0000000000000000 RDI: 000000000a01ffff
RBP: 000000000075bf20 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fae2eb936d4
R13: 00000000004bf72a R14: 00000000004d0e18 R15: 00000000ffffffff
Shutting down cpus with NMI
Kernel Offset: disabled
Rebooting in 86400 seconds..