================================================================== 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: __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 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