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BUG: KASAN: slab-out-of-bounds in tcp_retransmit_timer+0x2d30/0x3220 net/ipv4/tcp_timer.c:500
Read of size 8 at addr ffff88806066c390 by task syz-executor.4/20421

CPU: 1 PID: 20421 Comm: syz-executor.4 Not tainted 5.9.0-rc1-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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 tcp_retransmit_timer+0x2d30/0x3220 net/ipv4/tcp_timer.c:500
 tcp_write_timer_handler+0x79b/0xa60 net/ipv4/tcp_timer.c:611
 tcp_write_timer+0xa2/0x2b0 net/ipv4/tcp_timer.c:631
 call_timer_fn+0x1ac/0x760 kernel/time/timer.c:1413
 expire_timers kernel/time/timer.c:1458 [inline]
 __run_timers.part.0+0x67c/0xaa0 kernel/time/timer.c:1755
 __run_timers kernel/time/timer.c:1736 [inline]
 run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1768
 __do_softirq+0x2de/0xa24 kernel/softirq.c:298
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 do_softirq_own_stack+0x9d/0xd0 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:393 [inline]
 __irq_exit_rcu kernel/softirq.c:423 [inline]
 irq_exit_rcu+0x1f3/0x230 kernel/softirq.c:435
 sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581
RIP: 0010:write_comp_data+0x2f/0x80 kernel/kcov.c:218
Code: 05 d6 9a 8d 7e 65 48 8b 34 25 c0 fe 01 00 a9 00 01 ff 00 74 0f f6 c4 01 74 59 8b 86 44 14 00 00 85 c0 74 4f 8b 86 20 14 00 00 <83> f8 03 75 44 48 8b 86 28 14 00 00 8b b6 24 14 00 00 4c 8b 00 48
RSP: 0018:ffffc90005737780 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffffffff81a4b534
RDX: 0000000000000002 RSI: ffff888060dc6240 RDI: 0000000000000005
RBP: ffffea00027b1b30 R08: 0000000000000000 R09: ffffea00027b1b33
R10: 0000000000000000 R11: 0000000000000000 R12: ffffea00027b1b08
R13: ffffea00027b1b00 R14: dffffc0000000000 R15: 00007f7e7001f000
 zap_pte_range mm/memory.c:1092 [inline]
 zap_pmd_range mm/memory.c:1195 [inline]
 zap_pud_range mm/memory.c:1224 [inline]
 zap_p4d_range mm/memory.c:1245 [inline]
 unmap_page_range+0xf94/0x2b20 mm/memory.c:1266
 unmap_single_vma+0x198/0x300 mm/memory.c:1311
 unmap_vmas+0x168/0x2e0 mm/memory.c:1343
 exit_mmap+0x2b1/0x530 mm/mmap.c:3183
 __mmput+0x122/0x470 kernel/fork.c:1076
 mmput+0x53/0x60 kernel/fork.c:1097
 exit_mm kernel/exit.c:483 [inline]
 do_exit+0xa8b/0x29f0 kernel/exit.c:793
 do_group_exit+0x125/0x310 kernel/exit.c:903
 get_signal+0x428/0x1f00 kernel/signal.c:2757
 arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:136 [inline]
 exit_to_user_mode_prepare+0x15d/0x1c0 kernel/entry/common.c:167
 syscall_exit_to_user_mode+0x59/0x2b0 kernel/entry/common.c:242
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5b9
Code: Bad RIP value.
RSP: 002b:00007f7e6db99c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: fffffffffffffff2 RBX: 0000000000012cc0 RCX: 000000000045d5b9
RDX: 0000000000400200 RSI: 0000000000008912 RDI: 0000000000000003
RBP: 000000000118d020 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cfec
R13: 00007ffc4d045fef R14: 00007f7e6db9a9c0 R15: 000000000118cfec

Allocated by task 3912:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
 slab_post_alloc_hook mm/slab.h:518 [inline]
 slab_alloc mm/slab.c:3312 [inline]
 kmem_cache_alloc+0x138/0x3a0 mm/slab.c:3482
 getname_flags.part.0+0x50/0x4f0 fs/namei.c:138
 getname_flags fs/namei.c:2646 [inline]
 user_path_at_empty+0xa1/0x100 fs/namei.c:2646
 user_path_at include/linux/namei.h:59 [inline]
 vfs_statx+0x14e/0x390 fs/stat.c:202
 vfs_lstat include/linux/fs.h:3175 [inline]
 __do_sys_newlstat+0x91/0x110 fs/stat.c:374
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 3912:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422
 __cache_free mm/slab.c:3418 [inline]
 kmem_cache_free.part.0+0x67/0x1f0 mm/slab.c:3693
 putname+0xe1/0x120 fs/namei.c:259
 filename_lookup+0x3b1/0x560 fs/namei.c:2376
 user_path_at include/linux/namei.h:59 [inline]
 vfs_statx+0x14e/0x390 fs/stat.c:202
 vfs_lstat include/linux/fs.h:3175 [inline]
 __do_sys_newlstat+0x91/0x110 fs/stat.c:374
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88806066c5c0
 which belongs to the cache names_cache of size 4096
The buggy address is located 560 bytes to the left of
 4096-byte region [ffff88806066c5c0, ffff88806066d5c0)
The buggy address belongs to the page:
page:00000000928af229 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6066c
head:00000000928af229 order:1 compound_mapcount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea00019b2808 ffffea0001884408 ffff8880aa241c00
raw: 0000000000000000 ffff88806066c5c0 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88806066c280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88806066c300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88806066c380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff88806066c400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88806066c480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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