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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: 52d, last: 14d

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 ffff88812503e044 by task kworker/u4:3/296

CPU: 1 PID: 296 Comm: kworker/u4:3 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 415:
 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 411:
 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 ffff88812503e040
 which belongs to the cache net_namespace of size 4672
The buggy address is located 4 bytes inside of
 4672-byte region [ffff88812503e040, ffff88812503f280)
The buggy address belongs to the page:
page:ffffea0004940e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888125038000 pfn:0x125038
head:ffffea0004940e00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 ffffea0004441600 0000000300000003 ffff888107fdc600
raw: ffff888125038000 0000000080060003 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 276, ts 22154758851, 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:
 ffff88812503df00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff88812503df80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88812503e000: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
                                           ^
 ffff88812503e080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88812503e100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (613):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/14 07:12 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/13 22:59 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/13 20:12 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/13 12:56 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/13 10:52 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/13 09:22 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/12 22:07 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/12 09:29 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/12 08:26 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/12 06:46 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/12 04:33 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/12 03:30 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/12 01:06 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/11 21:05 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/11 19:55 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/11 18:18 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/11 12:40 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/11 08:47 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/11 03:30 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/10 21:01 android13-5.10-lts 59e9a7228857 3cda49cf .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
2025/07/10 03:30 android13-5.10-lts 59e9a7228857 956bd956 .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
2025/07/09 19:48 android13-5.10-lts 59e9a7228857 f4e5e155 .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
2025/07/09 17:51 android13-5.10-lts 59e9a7228857 f4e5e155 .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
2025/07/09 14:11 android13-5.10-lts 59e9a7228857 f4e5e155 .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
2025/07/09 08:47 android13-5.10-lts 59e9a7228857 f4e5e155 .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
2025/07/09 05:50 android13-5.10-lts 59e9a7228857 4d9fdfa4 .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
2025/07/09 03:26 android13-5.10-lts 59e9a7228857 4d9fdfa4 .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
2025/07/08 23:46 android13-5.10-lts 59e9a7228857 4d9fdfa4 .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
2025/07/08 15:34 android13-5.10-lts 59e9a7228857 4d9fdfa4 .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
2025/07/08 13:24 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/08 11:38 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/08 11:06 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/08 07:13 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/08 06:03 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/08 01:36 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/08 00:03 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/07 22:47 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/07 20:10 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/07 14:38 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/07 12:07 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/07 09:20 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/07 05:47 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/07 04:40 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/07 02:58 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/07 01:17 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/07 00:48 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/06 21:49 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/06 18:19 android13-5.10-lts 59e9a7228857 4f67c4ae .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
2025/07/06 15:36 android13-5.10-lts 59e9a7228857 4f67c4ae .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
* Struck through repros no longer work on HEAD.