==================================================================
BUG: KASAN: slab-out-of-bounds in tcp_retransmit_timer+0x2fc3/0x33f0 net/ipv4/tcp_timer.c:480
Read of size 8 at addr ffff888090ce0278 by task syz-executor.3/21883
CPU: 0 PID: 21883 Comm: syz-executor.3 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354
kasan_report mm/kasan/report.c:412 [inline]
__asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433
tcp_retransmit_timer+0x2fc3/0x33f0 net/ipv4/tcp_timer.c:480
tcp_write_timer_handler+0x5e6/0xa60 net/ipv4/tcp_timer.c:593
tcp_write_timer+0x103/0x1b0 net/ipv4/tcp_timer.c:613
call_timer_fn+0x177/0x700 kernel/time/timer.c:1338
expire_timers+0x243/0x4e0 kernel/time/timer.c:1375
__run_timers kernel/time/timer.c:1696 [inline]
run_timer_softirq+0x21c/0x670 kernel/time/timer.c:1709
__do_softirq+0x265/0x980 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:372 [inline]
irq_exit+0x215/0x260 kernel/softirq.c:412
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1098
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894
</IRQ>
RIP: 0010:write_comp_data+0x0/0x70 kernel/kcov.c:116
Code: 20 48 8b 88 68 13 00 00 8b 80 64 13 00 00 48 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 c3 0f 1f 84 00 00 00 00 00 <49> 89 f1 49 89 fa 65 48 8b 34 25 c0 df 01 00 65 8b 05 7a 59 9f 7e
RSP: 0018:ffff88804fc5fa60 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000003 RBX: ffff88808b6e19d8 RCX: ffffffff81b07021
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000005
RBP: ffff88808b6e1a38 R08: 0000000000000000 R09: ffffed10116dc347
R10: ffff88808b6e1a3b R11: 0000000000000000 R12: 0000000000000002
R13: ffff88804fc5fc48 R14: ffff88808b6e19d8 R15: 00000000627bc442
__brelse+0x51/0xa0 fs/buffer.c:1140
brelse include/linux/buffer_head.h:297 [inline]
recently_deleted fs/ext4/ialloc.c:709 [inline]
find_inode_bit+0x3b4/0x520 fs/ext4/ialloc.c:724
__ext4_new_inode+0x160c/0x5a20 fs/ext4/ialloc.c:916
ext4_mkdir+0x396/0xe10 fs/ext4/namei.c:2696
vfs_mkdir+0x508/0x7a0 fs/namei.c:3819
do_mkdirat+0x262/0x2d0 fs/namei.c:3842
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fbb2dc600e9
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbb2c5d5168 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00007fbb2dd72f60 RCX: 00007fbb2dc600e9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000180
RBP: 00007fbb2dcba08d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe16f6fcbf R14: 00007fbb2c5d5300 R15: 0000000000022000
Allocated by task 4700:
kmem_cache_alloc+0x122/0x370 mm/slab.c:3559
getname_flags+0xce/0x590 fs/namei.c:140
user_path_at_empty+0x2a/0x50 fs/namei.c:2609
do_readlinkat+0xcd/0x2f0 fs/stat.c:394
__do_sys_readlinkat fs/stat.c:421 [inline]
__se_sys_readlinkat fs/stat.c:418 [inline]
__x64_sys_readlinkat+0x93/0xf0 fs/stat.c:418
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 4700:
__cache_free mm/slab.c:3503 [inline]
kmem_cache_free+0x7f/0x260 mm/slab.c:3765
putname+0xe1/0x120 fs/namei.c:261
filename_lookup+0x3d0/0x5a0 fs/namei.c:2358
do_readlinkat+0xcd/0x2f0 fs/stat.c:394
__do_sys_readlinkat fs/stat.c:421 [inline]
__se_sys_readlinkat fs/stat.c:418 [inline]
__x64_sys_readlinkat+0x93/0xf0 fs/stat.c:418
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
The buggy address belongs to the object at ffff888090ce0ac0
which belongs to the cache names_cache of size 4096
The buggy address is located 2120 bytes to the left of
4096-byte region [ffff888090ce0ac0, ffff888090ce1ac0)
The buggy address belongs to the page:
page:ffffea0002433800 count:1 mapcount:0 mapping:ffff88823b843380 index:0x0 compound_mapcount: 0
flags: 0xfff00000008100(slab|head)
raw: 00fff00000008100 ffffea000152eb88 ffffea0002433888 ffff88823b843380
raw: 0000000000000000 ffff888090ce0ac0 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff888090ce0100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888090ce0180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888090ce0200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff888090ce0280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888090ce0300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
----------------
Code disassembly (best guess):
0: 20 48 8b and %cl,-0x75(%rax)
3: 88 68 13 mov %ch,0x13(%rax)
6: 00 00 add %al,(%rax)
8: 8b 80 64 13 00 00 mov 0x1364(%rax),%eax
e: 48 8b 11 mov (%rcx),%rdx
11: 48 83 c2 01 add $0x1,%rdx
15: 48 39 d0 cmp %rdx,%rax
18: 76 07 jbe 0x21
1a: 48 89 34 d1 mov %rsi,(%rcx,%rdx,8)
1e: 48 89 11 mov %rdx,(%rcx)
21: c3 retq
22: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1)
29: 00
* 2a: 49 89 f1 mov %rsi,%r9 <-- trapping instruction
2d: 49 89 fa mov %rdi,%r10
30: 65 48 8b 34 25 c0 df mov %gs:0x1dfc0,%rsi
37: 01 00
39: 65 8b 05 7a 59 9f 7e mov %gs:0x7e9f597a(%rip),%eax # 0x7e9f59ba