syzbot


KASAN: use-after-free Write in __mod_timer (3)

Status: upstream: reported on 2022/06/26 20:18
Reported-by: syzbot+0bc09403655fa5bb391c@syzkaller.appspotmail.com
First crash: 160d, last: 104d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-54 KASAN: use-after-free Write in __mod_timer 1 644d 644d 0/2 auto-closed as invalid on 2021/06/27 19:40
android-54 KASAN: use-after-free Write in __mod_timer (2) 1 428d 428d 0/2 auto-closed as invalid on 2022/01/30 03:03

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:796 [inline]
BUG: KASAN: use-after-free in enqueue_timer kernel/time/timer.c:541 [inline]
BUG: KASAN: use-after-free in __mod_timer+0x9a4/0x1a40 kernel/time/timer.c:1062
Write of size 8 at addr ffff8881e5d6f1c8 by task kworker/0:2/101

CPU: 0 PID: 101 Comm: kworker/0:2 Not tainted 5.4.197-syzkaller-00011-gf3c75e616e3f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Workqueue: wg-crypt-wg0 wg_packet_tx_worker
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18e/0x1d5 lib/dump_stack.c:118
 print_address_description+0x8c/0x630 mm/kasan/report.c:384
 __kasan_report+0xf6/0x130 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:653
 hlist_add_head include/linux/list.h:796 [inline]
 enqueue_timer kernel/time/timer.c:541 [inline]
 __mod_timer+0x9a4/0x1a40 kernel/time/timer.c:1062
 mod_peer_timer drivers/net/wireguard/timers.c:37 [inline]
 wg_timers_any_authenticated_packet_traversal+0x125/0x180 drivers/net/wireguard/timers.c:215
 wg_packet_create_data_done drivers/net/wireguard/send.c:247 [inline]
 wg_packet_tx_worker+0x15d/0x4d0 drivers/net/wireguard/send.c:276
 process_one_work+0x6ca/0xc40 kernel/workqueue.c:2287
 worker_thread+0xae0/0x1440 kernel/workqueue.c:2433
 kthread+0x2d8/0x360 kernel/kthread.c:288
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the page:
page:ffffea0007975bc0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x8000000000000000()
raw: 8000000000000000 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x146dc0(GFP_USER|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_COMP|__GFP_ZERO)
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2165 [inline]
 prep_new_page+0x194/0x380 mm/page_alloc.c:2171
 get_page_from_freelist+0x524/0x560 mm/page_alloc.c:3794
 __alloc_pages_nodemask+0x2ab/0x6f0 mm/page_alloc.c:4857
 __alloc_pages include/linux/gfp.h:503 [inline]
 __alloc_pages_node include/linux/gfp.h:516 [inline]
 alloc_pages_node include/linux/gfp.h:530 [inline]
 kmalloc_order mm/slab_common.c:1342 [inline]
 kmalloc_order_trace+0x2a/0xf0 mm/slab_common.c:1358
 __kmalloc_node include/linux/slab.h:422 [inline]
 kmalloc_node include/linux/slab.h:599 [inline]
 kvmalloc_node+0x7e/0xf0 mm/util.c:564
 kvmalloc include/linux/mm.h:758 [inline]
 kvzalloc include/linux/mm.h:766 [inline]
 alloc_netdev_mqs+0x86/0xc30 net/core/dev.c:9597
 tun_set_iff+0x4f9/0x1050 drivers/net/tun.c:2814
 __tun_chr_ioctl+0x6c7/0x1b70 drivers/net/tun.c:3149
 do_vfs_ioctl+0x6d1/0x15b0 fs/ioctl.c:47
 ksys_ioctl fs/ioctl.c:742 [inline]
 __do_sys_ioctl fs/ioctl.c:749 [inline]
 __se_sys_ioctl fs/ioctl.c:747 [inline]
 __x64_sys_ioctl+0xd4/0x110 fs/ioctl.c:747
 do_syscall_64+0xcb/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1176 [inline]
 __free_pages_ok+0x7ee/0x920 mm/page_alloc.c:1438
 free_the_page mm/page_alloc.c:4919 [inline]
 __free_pages+0x45/0x1e0 mm/page_alloc.c:4925
 kfree+0x1ef/0x260 mm/slub.c:4068
 device_release+0x70/0x1a0 drivers/base/core.c:1776
 kobject_cleanup lib/kobject.c:708 [inline]
 kobject_release+0x1f3/0x3d0 lib/kobject.c:739
 tun_set_iff+0xc0b/0x1050 drivers/net/tun.c:2906
 __tun_chr_ioctl+0x6c7/0x1b70 drivers/net/tun.c:3149
 do_vfs_ioctl+0x6d1/0x15b0 fs/ioctl.c:47
 ksys_ioctl fs/ioctl.c:742 [inline]
 __do_sys_ioctl fs/ioctl.c:749 [inline]
 __se_sys_ioctl fs/ioctl.c:747 [inline]
 __x64_sys_ioctl+0xd4/0x110 fs/ioctl.c:747
 do_syscall_64+0xcb/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Memory state around the buggy address:
 ffff8881e5d6f080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881e5d6f100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8881e5d6f180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff8881e5d6f200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881e5d6f280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-android-5-4-perf-kasan 2022/08/21 20:00 android12-5.4 f3c75e616e3f 26a13b38 .config log report info KASAN: use-after-free Write in __mod_timer
ci2-android-5-4-perf-kasan 2022/06/26 20:17 android12-5.4 9ce4508d6de9 a371c43c .config log report info KASAN: use-after-free Write in __mod_timer
* Struck through repros no longer work on HEAD.