RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200000c0
RBP: 00007fbd075381d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffefde4036f R14: 00007fbd07538300 R15: 0000000000022000
==================================================================
BUG: KASAN: use-after-free in tcp_retransmit_timer+0x245f/0x28c0 net/ipv4/tcp_timer.c:471
Read of size 8 at addr ffff88804f604278 by task swapper/1/0

CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.14.232-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:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load8_noabort+0x68/0x70 mm/kasan/report.c:430
 tcp_retransmit_timer+0x245f/0x28c0 net/ipv4/tcp_timer.c:471
 tcp_write_timer_handler+0x434/0x780 net/ipv4/tcp_timer.c:583
 tcp_write_timer+0xc8/0x160 net/ipv4/tcp_timer.c:601
 call_timer_fn+0x14a/0x650 kernel/time/timer.c:1280
 expire_timers+0x232/0x4d0 kernel/time/timer.c:1319
 __run_timers kernel/time/timer.c:1637 [inline]
 run_timer_softirq+0x1d5/0x5a0 kernel/time/timer.c:1650
 __do_softirq+0x24d/0x9ff kernel/softirq.c:288
 invoke_softirq kernel/softirq.c:368 [inline]
 irq_exit+0x193/0x240 kernel/softirq.c:409
 exiting_irq arch/x86/include/asm/apic.h:638 [inline]
 smp_apic_timer_interrupt+0x141/0x5e0 arch/x86/kernel/apic/apic.c:1106
 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793
 </IRQ>
RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61
RSP: 0018:ffff8880b5477e68 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10
RAX: 1ffffffff11e125c RBX: dffffc0000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff8880b5464bc4
RBP: ffffffff88f092d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffed1016a8c868
R13: ffff8880b5464340 R14: 0000000000000000 R15: 0000000000000000
 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline]
 default_idle+0x47/0x370 arch/x86/kernel/process.c:558
 cpuidle_idle_call kernel/sched/idle.c:156 [inline]
 do_idle+0x250/0x3c0 kernel/sched/idle.c:246
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:351
 start_secondary+0x4db/0x670 arch/x86/kernel/smpboot.c:272
 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240

Allocated by task 4624:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 kmem_cache_alloc+0x124/0x3c0 mm/slab.c:3552
 getname_flags+0xc8/0x550 fs/namei.c:138
 user_path_at_empty+0x2a/0x50 fs/namei.c:2631
 user_path_at include/linux/namei.h:57 [inline]
 SYSC_faccessat fs/open.c:403 [inline]
 SyS_faccessat+0x21b/0x680 fs/open.c:353
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 4624:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kmem_cache_free+0x7c/0x2b0 mm/slab.c:3758
 putname+0xcd/0x110 fs/namei.c:259
 filename_lookup+0x37b/0x510 fs/namei.c:2386
 user_path_at include/linux/namei.h:57 [inline]
 SYSC_faccessat fs/open.c:403 [inline]
 SyS_faccessat+0x21b/0x680 fs/open.c:353
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff88804f604000
 which belongs to the cache names_cache of size 4096
The buggy address is located 632 bytes inside of
 4096-byte region [ffff88804f604000, ffff88804f605000)
The buggy address belongs to the page:
page:ffffea00013d8100 count:1 mapcount:0 mapping:ffff88804f604000 index:0x0 compound_mapcount: 0
flags: 0xfff00000008100(slab|head)
raw: 00fff00000008100 ffff88804f604000 0000000000000000 0000000100000001
raw: ffffea00026948a0 ffffea00013d81a0 ffff88823f8bb200 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88804f604100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88804f604180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88804f604200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff88804f604280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88804f604300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================