bisecting fixing commit since 4762bcd451a9e92e79d5146d3d4a5ffe2b4e0ec5
building syzkaller on 048f2d494ee4a016e2386c28bf8cccdd87896cbd
testing commit 4762bcd451a9e92e79d5146d3d4a5ffe2b4e0ec5 with gcc (GCC) 8.1.0
kernel signature: ff2d6ac118bcf35bc382ce2c984c414c12f3d2e962505750c8cea5b064961f22
run #0: crashed: general protection fault in rxrpc_get_skb
run #1: crashed: BUG: unable to handle kernel NULL pointer dereference in rxrpc_send_data_packet
run #2: crashed: BUG: unable to handle kernel NULL pointer dereference in rxrpc_send_data_packet
run #3: crashed: BUG: unable to handle kernel NULL pointer dereference in rxrpc_send_data_packet
run #4: crashed: BUG: unable to handle kernel NULL pointer dereference in rxrpc_send_data_packet
run #5: crashed: BUG: unable to handle kernel NULL pointer dereference in rxrpc_send_data_packet
run #6: crashed: KASAN: use-after-free Read in rxrpc_see_skb
run #7: crashed: BUG: unable to handle kernel NULL pointer dereference in rxrpc_send_data_packet
run #8: crashed: BUG: unable to handle kernel NULL pointer dereference in rxrpc_send_data_packet
run #9: crashed: BUG: unable to handle kernel NULL pointer dereference in rxrpc_send_data_packet
testing current HEAD 78d697fc93f98054e36a3ab76dca1a88802ba7be
testing commit 78d697fc93f98054e36a3ab76dca1a88802ba7be with gcc (GCC) 8.1.0
kernel signature: cf157add9970be9f36f9441e5c8ded636ade3fbab15db9d193d824d0c384d398
run #0: crashed: KASAN: use-after-free Read in rxrpc_free_skb
run #1: crashed: general protection fault in rxrpc_get_skb
run #2: crashed: general protection fault in rxrpc_get_skb
run #3: crashed: general protection fault in rxrpc_get_skb
run #4: crashed: general protection fault in rxrpc_get_skb
run #5: crashed: general protection fault in rxrpc_get_skb
run #6: crashed: general protection fault in rxrpc_get_skb
run #7: crashed: general protection fault in rxrpc_get_skb
run #8: crashed: general protection fault in rxrpc_get_skb
run #9: crashed: general protection fault in rxrpc_get_skb
revisions tested: 2, total time: 25m31.302570083s (build: 17m12.609104836s, test: 7m5.291898862s)
the crash still happens on HEAD
commit msg: Linux 4.14.172
crash: general protection fault in rxrpc_get_skb
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 0 PID: 3 Comm: kworker/0:0 Not tainted 4.14.172-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: krxrpcd rxrpc_process_call
task: ffff8880a9c6c0c0 task.stack: ffff8880a9c78000
RIP: 0010:__read_once_size include/linux/compiler.h:183 [inline]
RIP: 0010:atomic_read arch/x86/include/asm/atomic.h:27 [inline]
RIP: 0010:refcount_read include/linux/refcount.h:42 [inline]
RIP: 0010:rxrpc_get_skb+0x57/0x2f0 net/rxrpc/skbuff.c:52
RSP: 0018:ffff8880a9c7fc60 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 00000000000000e4 RCX: 0000000000000000
RDX: 000000000000001c RSI: 000000000000000a RDI: 0000000000000000
RBP: ffff8880a9c7fca8 R08: ffff8880a9c6c9b0 R09: 00000000000053fc
R10: 0000000000000050 R11: ffff8880a9c6c0c0 R12: 000000000000000a
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000a56bf000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 rxrpc_resend net/rxrpc/call_event.c:319 [inline]
 rxrpc_process_call+0x4e1/0xff9 net/rxrpc/call_event.c:407
 process_one_work+0x79e/0x16c0 kernel/workqueue.c:2114
 worker_thread+0xcc/0xee0 kernel/workqueue.c:2248
 kthread+0x338/0x400 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: 89 45 d0 48 c7 c0 60 ad e0 89 48 0f 46 c2 f0 44 0f c1 28 48 8d 9f e4 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <0f> b6 14 02 48 89 d8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 
RIP: __read_once_size include/linux/compiler.h:183 [inline] RSP: ffff8880a9c7fc60
RIP: atomic_read arch/x86/include/asm/atomic.h:27 [inline] RSP: ffff8880a9c7fc60
RIP: refcount_read include/linux/refcount.h:42 [inline] RSP: ffff8880a9c7fc60
RIP: rxrpc_get_skb+0x57/0x2f0 net/rxrpc/skbuff.c:52 RSP: ffff8880a9c7fc60
---[ end trace fb3d9963109e0b4a ]---