bisecting fixing commit since 7d120bf21c05cbe30a679f0feeca884eeaceb069
building syzkaller on 36650b4b2c942bc382314dce384d311fbadd1208
testing commit 7d120bf21c05cbe30a679f0feeca884eeaceb069 with gcc (GCC) 8.1.0
kernel signature: f70b84fca0318666596c8dda0e6b23ddf6475472957e82989554ff664216d02e
all runs: crashed: general protection fault in tcp_splice_read
testing current HEAD fdc072324f3c66190a20f57490b4842a391d8233
testing commit fdc072324f3c66190a20f57490b4842a391d8233 with gcc (GCC) 8.1.0
kernel signature: f7cae64b904ac61e90cbffa6a57ee52f3502a40c8ddf8cc40301591c018184f6
all runs: crashed: general protection fault in tcp_splice_read
revisions tested: 2, total time: 34m56.157681355s (build: 18m47.85392817s, test: 15m3.744741491s)
the crash still happens on HEAD
commit msg: Linux 4.19.120
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: 8556 Comm: syz-executor.2 Not tainted 4.19.120-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:tcp_splice_read+0x140/0x8f0 net/ipv4/tcp.c:799
Code: fa 48 c1 ea 03 80 3c 02 00 0f 85 a2 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 34 06 00 00 31 c0 41 f6 44 24
RSP: 0018:ffff88809027fba8 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 1ffff1101204ff79 RCX: 1ffff1101497817f
RDX: 000000000000000f RSI: ffff8880a4bc0bd8 RDI: 0000000000000078
RBP: ffff88809027fcf0 R08: ffff8880a4bc0bf8 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88809027fcc8 R14: ffff88809027fe58 R15: ffff8880a5bb4f00
FS:  00007f66455e8700(0000) GS:ffff8880aea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000075c091 CR3: 00000000a0167000 CR4: 00000000001406f0
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+0xe40/0x12d0 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: 0033:0x45a919
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:00007f66455e7c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 000000000045a919
RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 000000000075bf20 R08: 000000000d86dac9 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f66455e86d4
R13: 00000000004cb45b R14: 00000000004e3ef0 R15: 00000000ffffffff
Modules linked in:
---[ end trace 4f6016b913e2c774 ]---
RIP: 0010:tcp_splice_read+0x140/0x8f0 net/ipv4/tcp.c:799
Code: fa 48 c1 ea 03 80 3c 02 00 0f 85 a2 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 34 06 00 00 31 c0 41 f6 44 24
RSP: 0018:ffff88809027fba8 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 1ffff1101204ff79 RCX: 1ffff1101497817f
RDX: 000000000000000f RSI: ffff8880a4bc0bd8 RDI: 0000000000000078
RBP: ffff88809027fcf0 R08: ffff8880a4bc0bf8 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88809027fcc8 R14: ffff88809027fe58 R15: ffff8880a5bb4f00
FS:  00007f66455e8700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c29b2e0928 CR3: 00000000a0167000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400