bisecting fixing commit since a68a0262abdaa251e12c53715f48e698a18ef402
building syzkaller on c090b4da255257841173fb4eb18c19d69b293180
testing commit a68a0262abdaa251e12c53715f48e698a18ef402 with gcc (GCC) 8.1.0
kernel signature: 92ef7a502368e377159912c7c622157146508e579cf0bdc44fb3a796a2749f5d
run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in ioctl_standard_call
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
reproducer seems to be flaky
testing current HEAD a0d54b4f5b219fb31f0776e9f53aa137e78ae431
testing commit a0d54b4f5b219fb31f0776e9f53aa137e78ae431 with gcc (GCC) 8.1.0
kernel signature: 47cb5477f5cdae5dd9a1eeca180a8a1ccca8c3d3117b44c61cb1a690e42768bd
run #0: crashed: BUG: unable to handle kernel NULL pointer dereference in ioctl_standard_call
run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in ioctl_standard_call
run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in ioctl_standard_call
run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in ioctl_standard_call
run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in ioctl_standard_call
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
Reproducer flagged being flaky
revisions tested: 2, total time: 27m4.402248723s (build: 9m7.040654078s, test: 17m24.718766811s)
the crash still happens on HEAD
commit msg: Merge tag 'trace-v5.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
crash: BUG: unable to handle kernel NULL pointer dereference in ioctl_standard_call
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 11e889067 P4D 11e889067 PUD 11f4e3067 PMD 0 
Oops: 0000 [#1] PREEMPT SMP
CPU: 0 PID: 455 Comm: syz-executor.5 Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:call_commit_handler net/wireless/wext-core.c:900 [inline]
RIP: 0010:ioctl_standard_call+0x9b/0x120 net/wireless/wext-core.c:1029
Code: 5e c3 4d 89 e8 4c 89 f1 48 89 da 44 89 e6 48 89 ef e8 c9 fb ff ff 83 f8 8d 75 da 49 8b 45 40 a8 01 74 29 49 8b 85 e0 01 00 00 <48> 8b 00 48 8b 00 48 85 c0 74 17 48 83 c4 08 4c 89 ef 31 c9 5b 31
RSP: 0018:ffffc9000436bdf8 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffffffff842ea630 RCX: 0000000000000006
RDX: 0000000000000000 RSI: ffffffff84b5ef61 RDI: ffffffff84a03de6
RBP: ffffc9000436be50 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000005 R12: 0000000000008b04
R13: ffff88811ef28000 R14: ffffffff83367b20 R15: 0000000000000000
FS:  00007f0d452f2700(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000011eb10000 CR4: 0000000000350ef0
Call Trace:
 wext_ioctl_dispatch net/wireless/wext-core.c:987 [inline]
 wext_handle_ioctl+0x9b/0xf0 net/wireless/wext-core.c:1048
 sock_ioctl+0x1d0/0x360 net/socket.c:1109
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x7c/0xb0 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e159
Code: 0d b4 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 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0d452f1c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045e159
RDX: 00000000200002c0 RSI: 0000000000008b04 RDI: 0000000000000007
RBP: 000000000119c110 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119c0dc
R13: 00007ffea04843df R14: 00007f0d452f29c0 R15: 000000000119c0dc
Modules linked in:
CR2: 0000000000000000
---[ end trace 3073184eeb588a29 ]---
RIP: 0010:call_commit_handler net/wireless/wext-core.c:900 [inline]
RIP: 0010:ioctl_standard_call+0x9b/0x120 net/wireless/wext-core.c:1029
Code: 5e c3 4d 89 e8 4c 89 f1 48 89 da 44 89 e6 48 89 ef e8 c9 fb ff ff 83 f8 8d 75 da 49 8b 45 40 a8 01 74 29 49 8b 85 e0 01 00 00 <48> 8b 00 48 8b 00 48 85 c0 74 17 48 83 c4 08 4c 89 ef 31 c9 5b 31
RSP: 0018:ffffc9000436bdf8 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffffffff842ea630 RCX: 0000000000000006
RDX: 0000000000000000 RSI: ffffffff84b5ef61 RDI: ffffffff84a03de6
RBP: ffffc9000436be50 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000005 R12: 0000000000008b04
R13: ffff88811ef28000 R14: ffffffff83367b20 R15: 0000000000000000
FS:  00007f0d452f2700(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000011eb10000 CR4: 0000000000350ef0