bisecting fixing commit since ef244c3088856cf048c77231653b4c92a7b2213c
building syzkaller on 5ea87a6638e52a94361b26b8576a1605585815fb
testing commit ef244c3088856cf048c77231653b4c92a7b2213c with gcc (GCC) 8.1.0
kernel signature: cf518c9f36ef1663a71860a793009f25e711fa30
run #0: crashed: KASAN: use-after-free Write in tls_push_record
run #1: crashed: KASAN: out-of-bounds Write in tls_push_record
run #2: crashed: KASAN: use-after-free Write in tls_push_record
run #3: crashed: KASAN: use-after-free Write in tls_push_record
run #4: crashed: KASAN: use-after-free Write in tls_push_record
run #5: crashed: KASAN: use-after-free Write in tls_push_record
run #6: crashed: KASAN: use-after-free Write in tls_push_record
run #7: crashed: KASAN: use-after-free Write in tls_push_record
run #8: crashed: KASAN: use-after-free Write in tls_push_record
run #9: crashed: KASAN: use-after-free Write in tls_push_record
testing current HEAD 3d40d7117e353b84627c1e8c5ed9ae0b1237ef5c
testing commit 3d40d7117e353b84627c1e8c5ed9ae0b1237ef5c with gcc (GCC) 8.1.0
kernel signature: 59f4dc338cc82859239ad8e7904d982b38c4fd43
run #0: crashed: KASAN: use-after-free Write in tls_push_record
run #1: crashed: KASAN: use-after-free Write in tls_push_record
run #2: crashed: general protection fault in tls_push_sg
run #3: crashed: KASAN: slab-out-of-bounds Write in tls_push_record
run #4: crashed: KASAN: slab-out-of-bounds Write in tls_push_record
run #5: crashed: general protection fault in tls_push_sg
run #6: crashed: KASAN: use-after-free Write in tls_push_record
run #7: crashed: kernel panic: corrupted stack end in corrupted
run #8: crashed: KASAN: use-after-free Write in tls_push_record
run #9: crashed: KASAN: use-after-free Write in tls_push_record
revisions tested: 2, total time: 25m30.633409067s (build: 17m31.682640146s, test: 6m37.22955058s)
the crash still happens on HEAD
commit msg: Linux 4.19.93
crash: KASAN: use-after-free Write in tls_push_record
IPv6: ADDRCONF(NETDEV_UP): veth0_to_hsr: link is not ready
RBP: 000000000075bf20 R08: 0000000000000000 R09: fffffffffffffe5b
R10: 0000000000000040 R11: 0000000000000246 R12: 00007fbaae7c46d4
R13: 00000000004c83ce R14: 00000000004de710 R15: 0000000000000006
==================================================================
BUG: KASAN: use-after-free in tls_fill_prepend include/net/tls.h:373 [inline]
BUG: KASAN: use-after-free in tls_push_record+0x127a/0x1720 net/tls/tls_sw.c:220
Write of size 1 at addr ffff88808d148000 by task syz-executor.1/7031

CPU: 0 PID: 7031 Comm: syz-executor.1 Not tainted 4.19.93-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
 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
 __asan_report_store1_noabort+0x17/0x20 mm/kasan/report.c:435
 tls_fill_prepend include/net/tls.h:373 [inline]
 tls_push_record+0x127a/0x1720 net/tls/tls_sw.c:220
 tls_sw_push_pending_record+0xe/0x10 net/tls/tls_sw.c:257
 tls_handle_open_record net/tls/tls_main.c:156 [inline]
 tls_sk_proto_close+0x5f6/0x8e0 net/tls/tls_main.c:271
 inet_release+0xd9/0x1c0 net/ipv4/af_inet.c:428
 inet6_release+0x46/0x60 net/ipv6/af_inet6.c:472
 __sock_release+0xc2/0x290 net/socket.c:579
 sock_close+0x10/0x20 net/socket.c:1140
 __fput+0x249/0x7f0 fs/file_table.c:278
 ____fput+0x9/0x10 fs/file_table.c:309
 task_work_run+0x108/0x180 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x1a9/0x200 arch/x86/entry/common.c:167
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x413ae1
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 1b 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007fff183be280 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000413ae1
RDX: 0000001b32020000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000001 R08: ffffffffffffffff R09: ffffffffffffffff
R10: 00007fff183be360 R11: 0000000000000293 R12: 000000000075c9a0
R13: 000000000075c9a0 R14: 00000000007612f0 R15: 000000000075bf2c

The buggy address belongs to the page:
page:ffffea0002345200 count:0 mapcount:-128 mapping:0000000000000000 index:0x0
flags: 0x1fffc0000000000()
raw: 01fffc0000000000 ffffea0002369e08 ffff88812fffc878 0000000000000000
raw: 0000000000000000 0000000000000003 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808d147f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88808d147f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88808d148000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88808d148080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88808d148100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================