bisecting fixing commit since 7d120bf21c05cbe30a679f0feeca884eeaceb069
building syzkaller on 36650b4b2c942bc382314dce384d311fbadd1208
testing commit 7d120bf21c05cbe30a679f0feeca884eeaceb069 with gcc (GCC) 8.4.1 20210217
kernel signature: 293ede4e6c659a7070a3bf4b81281632779900c47b681cb547be1f3b8717e13d
all runs: crashed: general protection fault in tcp_splice_read
testing current HEAD 97a8651cadce7c2b7c4d8f108b392eff31fe2c08
testing commit 97a8651cadce7c2b7c4d8f108b392eff31fe2c08 with gcc (GCC) 8.4.1 20210217
kernel signature: 5b1c72db72e6ca63e176c8acd33748a00d974046793fc99c3f1cbd3ccb941e5f
all runs: crashed: general protection fault in tcp_splice_read
revisions tested: 2, total time: 37m50.331853625s (build: 22m1.241248914s, test: 15m12.801980892s)
the crash still happens on HEAD
commit msg: Linux 4.19.189
crash: general protection fault in tcp_splice_read
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
CPU: 0 PID: 5967 Comm: syz-executor.0 Not tainted 4.19.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:tcp_splice_read+0x138/0x8d0 net/ipv4/tcp.c:809
Code: fa 48 c1 ea 03 80 3c 02 00 0f 85 18 07 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 64 24 18 49 8d 7c 24 78 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 20 06 00 00 31 c0 41 f6 44 24
RSP: 0018:ffff8881df06fba8 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 1ffff1103be0df79 RCX: 1ffff1103bf2f527
RDX: 000000000000000f RSI: ffff8881df97a918 RDI: 0000000000000078
RBP: ffff8881df06fcf0 R08: ffff8881df97a938 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8881df06fcc8 R15: ffff8881f3644f00
FS:  00007f985ffa1700(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000052c000 CR3: 00000001e3a72003 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 smc_splice_read+0x1f6/0x330 net/smc/af_smc.c:1855
 sock_splice_read+0x92/0x120 net/socket.c:859
 do_splice_to+0xe3/0x120 fs/splice.c:881
 do_splice+0xe36/0x12b0 fs/splice.c:1186
 __do_sys_splice fs/splice.c:1428 [inline]
 __se_sys_splice fs/splice.c:1408 [inline]
 __x64_sys_splice+0x248/0x300 fs/splice.c:1408
 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x462229
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f985ffa11a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 000000000052bfa8 RCX: 0000000000462229
RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 0000000000000006 R08: 000000000d86dac9 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004fcdd0 R14: 00000000004b6fb8 R15: 00007f985ffa16bc
Modules linked in:
---[ end trace 5754140947f218b7 ]---
RIP: 0010:tcp_splice_read+0x138/0x8d0 net/ipv4/tcp.c:809
Code: fa 48 c1 ea 03 80 3c 02 00 0f 85 18 07 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 64 24 18 49 8d 7c 24 78 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 20 06 00 00 31 c0 41 f6 44 24
RSP: 0018:ffff8881df06fba8 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 1ffff1103be0df79 RCX: 1ffff1103bf2f527
RDX: 000000000000000f RSI: ffff8881df97a918 RDI: 0000000000000078
RBP: ffff8881df06fcf0 R08: ffff8881df97a938 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff8881df06fcc8 R15: ffff8881f3644f00
FS:  00007f985ffa1700(0000) GS:ffff8881f6800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f496de4d000 CR3: 00000001e3a72002 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400