Hello,

syzbot found the following issue on:

HEAD commit: a6faf7ea9fcb Add linux-next specific files for 20230328 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=12e4a6d1c80000 kernel config: https://syzkaller.appspot.com/x/.config?x=dd9eb5678a80e926 dashboard link: https://syzkaller.appspot.com/bug?extid=6c3ddeb774a88806d35a compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/b03351a37b6b/disk-a6faf7ea.raw.... vmlinux: https://storage.googleapis.com/syzbot-assets/663c2ddae5f7/vmlinux-a6faf7ea.x... kernel image: https://storage.googleapis.com/syzbot-assets/a5e229b4773a/bzImage-a6faf7ea.x...

IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+6c3ddeb774a88806d35a@syzkaller.appspotmail.com

============================= [ BUG: Invalid wait context ] 6.3.0-rc4-next-20230328-syzkaller #0 Not tainted ----------------------------- kworker/u4:11/7080 is trying to lock: ffffffff916756d0 (lock_keys_hash){....}-{40:209}, at: spin_lock_bh include/linux/spinlock.h:355 [inline] ffffffff916756d0 (lock_keys_hash){....}-{40:209}, at: batadv_nc_process_nc_paths.part.0+0x142/0x3f0 net/batman-adv/network-coding.c:690 other info that might help us debug this: context-{4:4} 3 locks held by kworker/u4:11/7080: #0: ffff888026eef938 ((wq_completion)bat_events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] ((wq_completion)bat_events){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] ((wq_completion)bat_events){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline] ((wq_completion)bat_events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:643 [inline] ((wq_completion)bat_events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:670 [inline] ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work+0x883/0x15e0 kernel/workqueue.c:2376 #1: ffffc900033afdb0 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x8b7/0x15e0 kernel/workqueue.c:2380 #2: ffffffff8c795e00 (rcu_read_lock){....}-{1:2}, at: batadv_nc_process_nc_paths.part.0+0xb1/0x3f0 net/batman-adv/network-coding.c:684 stack backtrace: CPU: 1 PID: 7080 Comm: kworker/u4:11 Not tainted 6.3.0-rc4-next-20230328-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/17/2023 Workqueue: bat_events batadv_nc_worker Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 print_lock_invalid_wait_context kernel/locking/lockdep.c:4724 [inline] check_wait_context kernel/locking/lockdep.c:4785 [inline] __lock_acquire+0x159e/0x5df0 kernel/locking/lockdep.c:5024 lock_acquire.part.0+0x11c/0x370 kernel/locking/lockdep.c:5691 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:126 [inline] _raw_spin_lock_bh+0x33/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:355 [inline] batadv_nc_process_nc_paths.part.0+0x142/0x3f0 net/batman-adv/network-coding.c:690 batadv_nc_process_nc_paths net/batman-adv/network-coding.c:679 [inline] batadv_nc_worker+0xc82/0xfe0 net/batman-adv/network-coding.c:728 process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405 worker_thread+0x67d/0x10c0 kernel/workqueue.c:2552 kthread+0x33e/0x440 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 </TASK> ================================================================== BUG: KASAN: slab-out-of-bounds in batadv_nc_fwd_flush+0x422/0x4d0 net/batman-adv/network-coding.c:650 Read of size 4 at addr ffff88807a916130 by task kworker/u4:11/7080

CPU: 1 PID: 7080 Comm: kworker/u4:11 Not tainted 6.3.0-rc4-next-20230328-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/17/2023 Workqueue: bat_events batadv_nc_worker

Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351 print_report mm/kasan/report.c:462 [inline] kasan_report+0x11c/0x130 mm/kasan/report.c:572 batadv_nc_fwd_flush+0x422/0x4d0 net/batman-adv/network-coding.c:650 batadv_nc_process_nc_paths.part.0+0x1b6/0x3f0 net/batman-adv/network-coding.c:693 batadv_nc_process_nc_paths net/batman-adv/network-coding.c:679 [inline] batadv_nc_worker+0xc82/0xfe0 net/batman-adv/network-coding.c:728 process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405 worker_thread+0x67d/0x10c0 kernel/workqueue.c:2552 kthread+0x33e/0x440 kernel/kthread.c:379 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 </TASK>

Allocated by task 12301: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] ____kasan_kmalloc mm/kasan/common.c:333 [inline] __kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383 kmalloc include/linux/slab.h:559 [inline] kzalloc include/linux/slab.h:680 [inline] ref_tracker_alloc+0x158/0x580 lib/ref_tracker.c:85 __netdev_tracker_alloc include/linux/netdevice.h:4059 [inline] netdev_hold include/linux/netdevice.h:4088 [inline] netdev_hold include/linux/netdevice.h:4083 [inline] fib_check_nh_nongw net/ipv4/fib_semantics.c:1238 [inline] fib_check_nh+0x270/0x640 net/ipv4/fib_semantics.c:1258 fib_create_info+0x23b0/0x4c00 net/ipv4/fib_semantics.c:1553 fib_table_insert+0x199/0x1be0 net/ipv4/fib_trie.c:1236 fib_magic+0x493/0x580 net/ipv4/fib_frontend.c:1104 fib_add_ifaddr+0x4bc/0x560 net/ipv4/fib_frontend.c:1148 fib_netdev_event+0x38c/0x6f0 net/ipv4/fib_frontend.c:1486 notifier_call_chain+0xb6/0x3c0 kernel/notifier.c:93 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1937 call_netdevice_notifiers_extack net/core/dev.c:1975 [inline] call_netdevice_notifiers net/core/dev.c:1989 [inline] __dev_notify_flags+0x120/0x2d0 net/core/dev.c:8566 dev_change_flags+0x11b/0x170 net/core/dev.c:8604 do_setlink+0x9f4/0x3d30 net/core/rtnetlink.c:2836 rtnl_group_changelink net/core/rtnetlink.c:3380 [inline] __rtnl_newlink+0xb90/0x1840 net/core/rtnetlink.c:3636 rtnl_newlink+0x68/0xa0 net/core/rtnetlink.c:3673 rtnetlink_rcv_msg+0x43d/0xd50 net/core/rtnetlink.c:6388 netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2572 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x925/0xe30 net/netlink/af_netlink.c:1942 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg+0xde/0x190 net/socket.c:747 ____sys_sendmsg+0x71c/0x900 net/socket.c:2501 ___sys_sendmsg+0x110/0x1b0 net/socket.c:2555 __sys_sendmsg+0xf7/0x1c0 net/socket.c:2584 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff88807a916100 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 16 bytes to the right of allocated 32-byte region [ffff88807a916100, ffff88807a916120)

The buggy address belongs to the physical page: page:ffffea0001ea4580 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7a916 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000200 ffff888012441500 ffffea0001dedf40 dead000000000002 raw: 0000000000000000 0000000000400040 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 5781, tgid 5781 (syz-executor.4), ts 327417606587, free_ts 297066583858 prep_new_page mm/page_alloc.c:1729 [inline] get_page_from_freelist+0xf75/0x2aa0 mm/page_alloc.c:3493 __alloc_pages+0x1cb/0x4a0 mm/page_alloc.c:4759 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2283 alloc_slab_page mm/slub.c:1851 [inline] allocate_slab+0x28e/0x380 mm/slub.c:1998 new_slab mm/slub.c:2051 [inline] ___slab_alloc+0xa91/0x1400 mm/slub.c:3193 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3292 __slab_alloc_node mm/slub.c:3345 [inline] slab_alloc_node mm/slub.c:3442 [inline] __kmem_cache_alloc_node+0x136/0x320 mm/slub.c:3491 __do_kmalloc_node mm/slab_common.c:965 [inline] __kmalloc+0x4e/0x190 mm/slab_common.c:979 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:680 [inline] tomoyo_encode2.part.0+0xe9/0x3a0 security/tomoyo/realpath.c:45 tomoyo_encode2 security/tomoyo/realpath.c:31 [inline] tomoyo_encode+0x2c/0x50 security/tomoyo/realpath.c:80 tomoyo_path_perm+0x394/0x430 security/tomoyo/file.c:831 tomoyo_path_symlink+0x98/0xe0 security/tomoyo/tomoyo.c:211 security_path_symlink+0xe3/0x160 security/security.c:1747 do_symlinkat+0x10a/0x2e0 fs/namei.c:4422 __do_sys_symlinkat fs/namei.c:4440 [inline] __se_sys_symlinkat fs/namei.c:4437 [inline] __x64_sys_symlinkat+0x97/0xc0 fs/namei.c:4437 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1302 [inline] free_unref_page_prepare+0x4d8/0xb80 mm/page_alloc.c:2555 free_unref_page+0x33/0x370 mm/page_alloc.c:2650 qlink_free mm/kasan/quarantine.c:166 [inline] qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:185 kasan_quarantine_reduce+0x195/0x220 mm/kasan/quarantine.c:292 __kasan_slab_alloc+0x63/0x90 mm/kasan/common.c:305 kasan_slab_alloc include/linux/kasan.h:186 [inline] slab_post_alloc_hook mm/slab.h:711 [inline] slab_alloc_node mm/slub.c:3452 [inline] __kmem_cache_alloc_node+0x17c/0x320 mm/slub.c:3491 __do_kmalloc_node mm/slab_common.c:965 [inline] __kmalloc+0x4e/0x190 mm/slab_common.c:979 kmalloc include/linux/slab.h:563 [inline] tomoyo_realpath_from_path+0xc3/0x600 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x29a/0x3a0 security/tomoyo/file.c:771 tomoyo_file_open security/tomoyo/tomoyo.c:332 [inline] tomoyo_file_open+0xa1/0xc0 security/tomoyo/tomoyo.c:327 security_file_open+0x49/0xb0 security/security.c:2797 do_dentry_open+0x575/0x13f0 fs/open.c:907 do_open fs/namei.c:3560 [inline] path_openat+0x1baa/0x2750 fs/namei.c:3715 do_filp_open+0x1ba/0x410 fs/namei.c:3742 do_sys_openat2+0x16d/0x4c0 fs/open.c:1356 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x143/0x1f0 fs/open.c:1383

Memory state around the buggy address: ffff88807a916000: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc ffff88807a916080: 00 00 00 00 fc fc fc fc 00 00 05 fc fc fc fc fc

ffff88807a916100: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc

^ ffff88807a916180: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc ffff88807a916200: 00 00 00 00 fc fc fc fc 00 00 04 fc fc fc fc fc ==================================================================

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