syzbot

 sign-in | mailing list | source | docs
🐞 Open [977] ≡ Subsystems 🐞 Fixed [5235] 🐞 Invalid [12492] ⬇ Missing Backports [83] 📈 Kernel Health 📈 Bug Lifetimes 📈 Fuzzing 📈 Crashes 💬 Send us feedback

KASAN: slab-out-of-bounds Read in tcp_write_timer_handler (3)

Status: auto-closed as invalid on 2020/12/30 02:27
Subsystems: net
[Documentation on labels]
First crash: 1511d, last: 1300d
▶ ▼ Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-out-of-bounds Read in tcp_write_timer_handler net 1 1828d 1828d 0/26 closed as invalid on 2019/05/15 23:07
upstream KASAN: slab-out-of-bounds Read in tcp_write_timer_handler (2) net 24 1687d 1733d 0/26 auto-closed as invalid on 2019/12/08 17:54
upstream KASAN: slab-out-of-bounds Read in tcp_write_timer_handler (4) net 1 1187d 1187d 0/26 auto-closed as invalid on 2021/04/22 06:03
linux-4.19 KASAN: slab-out-of-bounds Read in tcp_write_timer_handler 1 1316d 1316d 0/1 auto-closed as invalid on 2021/01/13 10:13
linux-4.19 KASAN: use-after-free Read in tcp_write_timer_handler (2) 12 573d 1088d 0/1 auto-obsoleted due to no activity on 2023/01/25 19:39
upstream KASAN: use-after-free Read in tcp_write_timer_handler (4) net 529 496d 1522d 0/26 closed as invalid on 2023/03/21 22:54

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in tcp_probe_timer net/ipv4/tcp_timer.c:372 [inline]
BUG: KASAN: slab-out-of-bounds in tcp_write_timer_handler+0x9d0/0xa60 net/ipv4/tcp_timer.c:615
Read of size 4 at addr ffff88809390e77c by task syz-executor.4/2124

CPU: 0 PID: 2124 Comm: syz-executor.4 Not tainted 5.8.0-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/0x436 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 tcp_probe_timer net/ipv4/tcp_timer.c:372 [inline]
 tcp_write_timer_handler+0x9d0/0xa60 net/ipv4/tcp_timer.c:615
 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:arch_local_irq_restore arch/x86/include/asm/paravirt.h:770 [inline]
RIP: 0010:lock_acquire+0x27b/0xad0 kernel/locking/lockdep.c:5008
Code: 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 f8 06 00 00 48 83 3d fa ba 5b 08 00 0f 84 a6 05 00 00 48 8b 7c 24 08 57 9d <0f> 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 48 03 44 24 10 48 c7
RSP: 0018:ffffc90005177b78 EFLAGS: 00000286
RAX: 1ffffffff136c689 RBX: ffff8880531ee080 RCX: ffffffff815a212b
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000286
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8c5e3a37
R10: fffffbfff18bc746 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff89c83c60 R14: 0000000000000000 R15: ffff8880531ee080
 __fs_reclaim_acquire mm/page_alloc.c:4183 [inline]
 fs_reclaim_acquire+0x2f/0x40 mm/page_alloc.c:4194
 slab_pre_alloc_hook mm/slab.h:564 [inline]
 slab_alloc mm/slab.c:3306 [inline]
 kmem_cache_alloc+0x22/0x3b0 mm/slab.c:3484
 kmem_cache_zalloc include/linux/slab.h:659 [inline]
 __alloc_file+0x21/0x350 fs/file_table.c:101
 alloc_empty_file+0x6d/0x170 fs/file_table.c:151
 alloc_file+0x5e/0x5a0 fs/file_table.c:193
 alloc_file_pseudo+0x165/0x250 fs/file_table.c:233
 sock_alloc_file+0x4f/0x190 net/socket.c:411
 __sys_socketpair+0x32e/0x570 net/socket.c:1609
 __do_sys_socketpair net/socket.c:1631 [inline]
 __se_sys_socketpair net/socket.c:1628 [inline]
 __x64_sys_socketpair+0x93/0xf0 net/socket.c:1628
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45ce79
Code: 2d b6 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 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f9d5bb2dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 0000000000032b80 RCX: 000000000045ce79
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000001
RBP: 000000000118bf68 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000040 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007ffc73d3266f R14: 00007f9d5bb2e9c0 R15: 000000000118bf2c

Allocated by task 3898:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494
 slab_post_alloc_hook mm/slab.h:586 [inline]
 slab_alloc mm/slab.c:3320 [inline]
 kmem_cache_alloc+0x12c/0x3b0 mm/slab.c:3484
 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
 do_readlinkat+0xcd/0x2f0 fs/stat.c:419
 __do_sys_readlinkat fs/stat.c:446 [inline]
 __se_sys_readlinkat fs/stat.c:443 [inline]
 __x64_sys_readlinkat+0x93/0xf0 fs/stat.c:443
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 3898:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kmem_cache_free+0x7f/0x310 mm/slab.c:3694
 putname+0xe1/0x120 fs/namei.c:259
 filename_lookup+0x3b1/0x560 fs/namei.c:2376
 do_readlinkat+0xcd/0x2f0 fs/stat.c:419
 __do_sys_readlinkat fs/stat.c:446 [inline]
 __se_sys_readlinkat fs/stat.c:443 [inline]
 __x64_sys_readlinkat+0x93/0xf0 fs/stat.c:443
 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 ffff88809390ee80
 which belongs to the cache names_cache of size 4096
The buggy address is located 1796 bytes to the left of
 4096-byte region [ffff88809390ee80, ffff88809390fe80)
The buggy address belongs to the page:
page:ffffea00024e4380 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 head:ffffea00024e4380 order:1 compound_mapcount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea00012f9708 ffffea0002524c08 ffff88821bc51380
raw: 0000000000000000 ffff88809390ee80 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809390e600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809390e680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88809390e700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                                ^
 ffff88809390e780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809390e800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/08/08 09:07 upstream 5631c5e0eb90 ff51e522 .config console log report ci-upstream-kasan-gce-root
2020/03/03 21:23 upstream 63623fd44972 c88c7b75 .config console log report ci-upstream-kasan-gce-selinux-root
2020/10/01 02:25 bpf 9cf51446e686 8516f6d3 .config console log report info ci-upstream-bpf-kasan-gce
2020/09/02 07:26 bpf 1eb832ac2dee abf9ba4f .config console log report ci-upstream-bpf-kasan-gce
2020/07/23 00:27 net-old 2c4dc3148603 340ea530 .config console log report ci-upstream-net-this-kasan-gce
2020/08/21 04:13 bpf-next 149cb3395504 1d75fe45 .config console log report ci-upstream-bpf-next-kasan-gce
2020/08/09 08:32 net-next-old bfdd5aaa54b0 f721e4a0 .config console log report ci-upstream-net-kasan-gce
2020/07/19 18:37 bpf-next e57892f50a07 9c812472 .config console log report ci-upstream-bpf-next-kasan-gce
2020/05/18 20:25 bpf-next 96586dd9268d 684d3606 .config console log report ci-upstream-bpf-next-kasan-gce
2020/09/16 13:48 linux-next 5fa35f247b56 18d7d030 .config console log report info ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.