bisecting fixing commit since 9f31eb60d7a23536bf3902d4dc602f10c822b79e
building syzkaller on 34bf9440bd06034f86b5d9ac8afbf078129cbdae
testing commit 9f31eb60d7a23536bf3902d4dc602f10c822b79e with gcc (GCC) 8.1.0
kernel signature: 9f530c0c267dcc311524c024e36d81c328de05e3f8195e84f0a161f42a78319f
run #0: crashed: general protection fault in scatterwalk_copychunks
run #1: crashed: general protection fault in scatterwalk_copychunks
run #2: crashed: KASAN: slab-out-of-bounds Read in scatterwalk_copychunks
run #3: crashed: KASAN: slab-out-of-bounds Read in scatterwalk_copychunks
run #4: crashed: KASAN: slab-out-of-bounds Read in scatterwalk_copychunks
run #5: crashed: general protection fault in scatterwalk_copychunks
run #6: crashed: KASAN: slab-out-of-bounds Read in scatterwalk_copychunks
run #7: crashed: KASAN: slab-out-of-bounds Read in scatterwalk_copychunks
run #8: crashed: general protection fault in scatterwalk_copychunks
run #9: crashed: KASAN: slab-out-of-bounds Read in scatterwalk_copychunks
testing current HEAD f6d5cb9e2c06f7d583dd9f4f7cca21d13d78c32a
testing commit f6d5cb9e2c06f7d583dd9f4f7cca21d13d78c32a with gcc (GCC) 8.1.0
kernel signature: 8188841f8801dc35523a2f7ad2aca9047bc2ad121e9706e4b3fe364c03bb8c1e
run #0: crashed: KASAN: slab-out-of-bounds Read in scatterwalk_copychunks
run #1: crashed: KASAN: slab-out-of-bounds Read in scatterwalk_copychunks
run #2: crashed: general protection fault in scatterwalk_copychunks
run #3: crashed: KASAN: slab-out-of-bounds Read in scatterwalk_copychunks
run #4: crashed: general protection fault in scatterwalk_copychunks
run #5: crashed: general protection fault in scatterwalk_copychunks
run #6: crashed: general protection fault in scatterwalk_copychunks
run #7: crashed: general protection fault in scatterwalk_copychunks
run #8: crashed: general protection fault in scatterwalk_copychunks
run #9: crashed: KASAN: slab-out-of-bounds Read in scatterwalk_copychunks
revisions tested: 2, total time: 26m2.381735228s (build: 18m34.389594427s, test: 5m50.110405723s)
the crash still happens on HEAD
commit msg: Linux 4.19.142
crash: KASAN: slab-out-of-bounds Read in scatterwalk_copychunks
RBP: 000000000075bf20 R08: 0000000100000300 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007efe5ab706d4
R13: 00000000004c887b R14: 00000000004de6b0 R15: 0000000000000005
==================================================================
IPv6: ADDRCONF(NETDEV_UP): hsr0: link is not ready
BUG: KASAN: slab-out-of-bounds in memcpy include/linux/string.h:373 [inline]
BUG: KASAN: slab-out-of-bounds in memcpy_dir crypto/scatterwalk.c:28 [inline]
BUG: KASAN: slab-out-of-bounds in scatterwalk_copychunks+0x1e1/0x610 crypto/scatterwalk.c:43
8021q: adding VLAN 0 to HW filter on device batadv0
Read of size 4094 at addr ffff888099c1e000 by task syz-executor.0/7162

CPU: 1 PID: 7162 Comm: syz-executor.0 Not tainted 4.19.142-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
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 memcpy+0x23/0x50 mm/kasan/kasan.c:302
 memcpy include/linux/string.h:373 [inline]
 memcpy_dir crypto/scatterwalk.c:28 [inline]
 scatterwalk_copychunks+0x1e1/0x610 crypto/scatterwalk.c:43
 scatterwalk_map_and_copy+0x128/0x190 crypto/scatterwalk.c:72
 gcmaes_encrypt.constprop.15+0x6d6/0xda0 arch/x86/crypto/aesni-intel_glue.c:956
 generic_gcmaes_encrypt+0xfd/0x150 arch/x86/crypto/aesni-intel_glue.c:1297
 crypto_aead_encrypt include/crypto/aead.h:335 [inline]
 gcmaes_wrapper_encrypt+0x109/0x180 arch/x86/crypto/aesni-intel_glue.c:1130
 crypto_aead_encrypt include/crypto/aead.h:335 [inline]
 tls_do_encryption net/tls/tls_sw.c:193 [inline]
 tls_push_record+0x9ae/0x1600 net/tls/tls_sw.c:228
 tls_sw_sendpage+0x458/0xc00 net/tls/tls_sw.c:585
 inet_sendpage+0x122/0x600 net/ipv4/af_inet.c:815
 kernel_sendpage+0x60/0xd0 net/socket.c:3378
 sock_sendpage+0x6d/0xd0 net/socket.c:847
 pipe_to_sendpage+0x212/0x430 fs/splice.c:452
 splice_from_pipe_feed fs/splice.c:503 [inline]
 __splice_from_pipe+0x2cb/0x720 fs/splice.c:627
 splice_from_pipe+0xbb/0x120 fs/splice.c:662
 generic_splice_sendpage+0x10/0x20 fs/splice.c:833
 do_splice_from fs/splice.c:852 [inline]
 do_splice+0x4fd/0x12d0 fs/splice.c:1154
 __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: 0033:0x459349
Code: 7d b7 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 4b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007efe5ab6fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 00007efe5ab6fc90 RCX: 0000000000459349
RDX: 0000000000000004 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000100000300 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007efe5ab706d4
R13: 00000000004c887b R14: 00000000004de6b0 R15: 0000000000000005

Allocated by task 1:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
 kmem_cache_alloc_trace+0x152/0x740 mm/slab.c:3625
 kmalloc include/linux/slab.h:515 [inline]
 kzalloc include/linux/slab.h:709 [inline]
 alloc_super fs/super.c:200 [inline]
 sget_userns+0xd1/0xb70 fs/super.c:519
 kernfs_mount_ns+0x123/0x7e0 fs/kernfs/mount.c:325
 sysfs_mount+0xb4/0x1a0 fs/sysfs/mount.c:36
 mount_fs+0x7f/0x2a2 fs/super.c:1261
 vfs_kern_mount.part.34+0x58/0x3d0 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2469 [inline]
 do_mount+0x36e/0x2410 fs/namespace.c:2799
 ksys_mount+0xba/0xe0 fs/namespace.c:3015
 __do_sys_mount fs/namespace.c:3029 [inline]
 __se_sys_mount fs/namespace.c:3026 [inline]
 __x64_sys_mount+0xb9/0x150 fs/namespace.c:3026
 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff888099c1ed00
 which belongs to the cache kmalloc-4096 of size 4096
The buggy address is located 3328 bytes to the left of
 4096-byte region [ffff888099c1ed00, ffff888099c1fd00)
The buggy address belongs to the page:
page:ffffea0002670780 count:1 mapcount:0 mapping:ffff88812c31edc0 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000008100(slab|head)
raw: 01fffc0000008100 ffffea00026a6808 ffffea000267a308 ffff88812c31edc0
raw: 0000000000000000 ffff888099c1ed00 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888099c1df00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888099c1df80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888099c1e000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff888099c1e080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888099c1e100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================