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KASAN: use-after-free Read in tcp_net_metrics_exit_batch

Status: premoderation: reported on 2025/06/05 20:38
Reported-by: syzbot+f3ffa8ef97daf83b488c@syzkaller.appspotmail.com
First crash: 28d, last: 1h23m

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:27 [inline]
BUG: KASAN: use-after-free in refcount_read include/linux/refcount.h:147 [inline]
BUG: KASAN: use-after-free in tcp_metrics_flush_all net/ipv4/tcp_metrics.c:909 [inline]
BUG: KASAN: use-after-free in tcp_net_metrics_exit_batch+0x93/0x1a0 net/ipv4/tcp_metrics.c:1036
Read of size 4 at addr ffff888125146044 by task kworker/u4:0/7

CPU: 0 PID: 7 Comm: kworker/u4:0 Tainted: G        W         5.10.238-syzkaller-00008-g59e9a7228857 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack+0x21/0x24 lib/dump_stack.c:77
 dump_stack_lvl+0x169/0x1d8 lib/dump_stack.c:118
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0xe2/0x130 mm/kasan/report.c:452
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x280/0x290 mm/kasan/generic.c:189
 __kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 atomic_read include/asm-generic/atomic-instrumented.h:27 [inline]
 refcount_read include/linux/refcount.h:147 [inline]
 tcp_metrics_flush_all net/ipv4/tcp_metrics.c:909 [inline]
 tcp_net_metrics_exit_batch+0x93/0x1a0 net/ipv4/tcp_metrics.c:1036
 ops_exit_list net/core/net_namespace.c:190 [inline]
 cleanup_net+0x5fb/0xb70 net/core/net_namespace.c:609
 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301
 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447
 kthread+0x346/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

Allocated by task 275:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:430 [inline]
 __kasan_slab_alloc+0xbd/0xf0 mm/kasan/common.c:463
 kasan_slab_alloc include/linux/kasan.h:244 [inline]
 slab_post_alloc_hook+0x5d/0x2f0 mm/slab.h:583
 slab_alloc_node mm/slub.c:2947 [inline]
 slab_alloc mm/slub.c:2955 [inline]
 kmem_cache_alloc+0x165/0x2e0 mm/slub.c:2960
 kmem_cache_zalloc include/linux/slab.h:654 [inline]
 net_alloc net/core/net_namespace.c:421 [inline]
 copy_net_ns+0x13f/0x520 net/core/net_namespace.c:473
 create_new_namespaces+0x3a2/0x650 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x120/0x170 kernel/nsproxy.c:231
 ksys_unshare+0x4ac/0x7d0 kernel/fork.c:3156
 __do_sys_unshare kernel/fork.c:3224 [inline]
 __se_sys_unshare kernel/fork.c:3222 [inline]
 __x64_sys_unshare+0x38/0x40 kernel/fork.c:3222
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Freed by task 7:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:362
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370
 kasan_slab_free include/linux/kasan.h:220 [inline]
 slab_free_hook mm/slub.c:1595 [inline]
 slab_free_freelist_hook+0xc5/0x190 mm/slub.c:1621
 slab_free mm/slub.c:3203 [inline]
 kmem_cache_free+0x100/0x2d0 mm/slub.c:3219
 net_free net/core/net_namespace.c:449 [inline]
 net_drop_ns net/core/net_namespace.c:456 [inline]
 cleanup_net+0xae3/0xb70 net/core/net_namespace.c:630
 process_one_work+0x6e1/0xba0 kernel/workqueue.c:2301
 worker_thread+0xa6a/0x13b0 kernel/workqueue.c:2447
 kthread+0x346/0x3d0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

The buggy address belongs to the object at ffff888125146040
 which belongs to the cache net_namespace of size 4672
The buggy address is located 4 bytes inside of
 4672-byte region [ffff888125146040, ffff888125147280)
The buggy address belongs to the page:
page:ffffea0004945000 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888125140000 pfn:0x125140
head:ffffea0004945000 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 ffffea0004984200 0000000200000002 ffff888107fdd200
raw: ffff888125140000 0000000080060005 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 275, ts 24166506873, free_ts 0
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x179/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2235/0x23d0 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x268/0x5f0 mm/page_alloc.c:5357
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1808 [inline]
 new_slab+0x84/0x3f0 mm/slub.c:1869
 new_slab_objects mm/slub.c:2627 [inline]
 ___slab_alloc+0x2a6/0x450 mm/slub.c:2791
 __slab_alloc+0x63/0xa0 mm/slub.c:2831
 slab_alloc_node mm/slub.c:2913 [inline]
 slab_alloc mm/slub.c:2955 [inline]
 kmem_cache_alloc+0x1af/0x2e0 mm/slub.c:2960
 kmem_cache_zalloc include/linux/slab.h:654 [inline]
 net_alloc net/core/net_namespace.c:421 [inline]
 copy_net_ns+0x13f/0x520 net/core/net_namespace.c:473
 create_new_namespaces+0x3a2/0x650 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x120/0x170 kernel/nsproxy.c:231
 ksys_unshare+0x4ac/0x7d0 kernel/fork.c:3156
 __do_sys_unshare kernel/fork.c:3224 [inline]
 __se_sys_unshare kernel/fork.c:3222 [inline]
 __x64_sys_unshare+0x38/0x40 kernel/fork.c:3222
 do_syscall_64+0x31/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888125145f00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff888125145f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888125146000: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
                                           ^
 ffff888125146080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888125146100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (496):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/04 11:52 android13-5.10-lts 59e9a7228857 76ad128c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/04 09:44 android13-5.10-lts 59e9a7228857 76ad128c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/04 02:53 android13-5.10-lts 59e9a7228857 76ad128c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/03 23:02 android13-5.10-lts 59e9a7228857 76ad128c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/03 21:05 android13-5.10-lts 59e9a7228857 115ceea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/03 19:36 android13-5.10-lts 59e9a7228857 115ceea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/03 15:27 android13-5.10-lts 59e9a7228857 115ceea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/03 14:13 android13-5.10-lts 59e9a7228857 115ceea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/03 04:58 android13-5.10-lts 59e9a7228857 115ceea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/02 23:06 android13-5.10-lts 59e9a7228857 bc80e4f0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/02 21:38 android13-5.10-lts 59e9a7228857 bc80e4f0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/02 20:32 android13-5.10-lts 59e9a7228857 bc80e4f0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/02 16:28 android13-5.10-lts 59e9a7228857 bc80e4f0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/02 04:05 android13-5.10-lts 59e9a7228857 bc80e4f0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/01 15:41 android13-5.10-lts 59e9a7228857 091a06cd .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/01 14:39 android13-5.10-lts 59e9a7228857 091a06cd .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/01 13:26 android13-5.10-lts 59e9a7228857 6e83b42d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/07/01 07:18 android13-5.10-lts 59e9a7228857 6e83b42d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/30 18:48 android13-5.10-lts 59e9a7228857 6e83b42d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/30 17:42 android13-5.10-lts 59e9a7228857 6e83b42d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/30 16:15 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/30 12:02 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/30 08:38 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/30 07:35 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/30 07:25 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/30 01:17 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/29 23:19 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/29 19:30 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/29 15:14 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/29 12:49 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/29 11:10 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/29 08:45 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/29 07:13 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/29 04:58 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/28 21:36 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/28 20:32 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/28 16:31 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/28 15:26 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/28 12:32 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/28 11:07 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/28 10:04 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/27 22:28 android13-5.10-lts 59e9a7228857 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/27 17:19 android13-5.10-lts 59e9a7228857 803ce19b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/27 14:21 android13-5.10-lts 59e9a7228857 803ce19b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/27 11:25 android13-5.10-lts 59e9a7228857 803ce19b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/27 06:51 android13-5.10-lts 59e9a7228857 803ce19b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/27 03:28 android13-5.10-lts 59e9a7228857 803ce19b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/26 22:04 android13-5.10-lts 59e9a7228857 803ce19b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/26 10:02 android13-5.10-lts 59e9a7228857 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/26 05:24 android13-5.10-lts 59e9a7228857 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/26 01:01 android13-5.10-lts 59e9a7228857 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
2025/06/19 19:27 android13-5.10-lts d76d4cd0623a ed3e87f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-10 KASAN: use-after-free Read in tcp_net_metrics_exit_batch
* Struck through repros no longer work on HEAD.