netlink: 1010 bytes leftover after parsing attributes in process `syz.2.6300'.
bridge: RTM_NEWNEIGH bridge0 without NUD_PERMANENT
==================================================================
BUG: KCSAN: data-race in _prb_read_valid / prb_reserve

write to 0xffffffff86cc4b60 of 88 bytes by task 26590 on cpu 0:
 prb_reserve+0x6fb/0xaf0 kernel/printk/printk_ringbuffer.c:1693
 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354
 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2455
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2504
 __ext4_error_inode+0x298/0x3a0 fs/ext4/super.c:861
 __ext4_mark_inode_dirty+0xbd/0x3d0 fs/ext4/inode.c:6613
 __ext4_ext_dirty+0xda/0x1f0 fs/ext4/extents.c:207
 ext4_ext_remove_space+0x26dd/0x28b0 fs/ext4/extents.c:3080
 ext4_ext_truncate+0xc7/0x160 fs/ext4/extents.c:4566
 ext4_truncate+0x6e8/0xa10 fs/ext4/inode.c:4668
 ext4_evict_inode+0x952/0xdf0 fs/ext4/inode.c:274
 evict+0x2a5/0x510 fs/inode.c:825
 iput_final fs/inode.c:2019 [inline]
 iput+0x430/0x5a0 fs/inode.c:2068
 filename_unlinkat+0x21f/0x410 fs/namei.c:5589
 __do_sys_unlink fs/namei.c:5620 [inline]
 __se_sys_unlink+0x2b/0xe0 fs/namei.c:5617
 __x64_sys_unlink+0x1f/0x30 fs/namei.c:5617
 x64_sys_call+0x2eb6/0x3020 arch/x86/include/generated/asm/syscalls_64.h:88
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86cc4b60 of 8 bytes by task 26602 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:500 [inline]
 desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1934 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1982 [inline]
 _prb_read_valid+0x18c/0x930 kernel/printk/printk_ringbuffer.c:2173
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2245
 printk_get_next_message+0xea/0x550 kernel/printk/printk.c:3052
 console_emit_next_record kernel/printk/printk.c:3137 [inline]
 console_flush_one_record kernel/printk/printk.c:3269 [inline]
 console_flush_all+0x2bc/0x6b0 kernel/printk/printk.c:3343
 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
 console_unlock+0xa1/0x280 kernel/printk/printk.c:3413
 vprintk_emit+0x3e4/0x600 kernel/printk/printk.c:2479
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2504
 fdb_add_entry net/bridge/br_fdb.c:1166 [inline]
 __br_fdb_add+0x62b/0x950 net/bridge/br_fdb.c:1275
 br_fdb_add+0x3a6/0x680 net/bridge/br_fdb.c:1358
 rtnl_fdb_add+0x4d3/0x680 net/core/rtnetlink.c:4784
 rtnetlink_rcv_msg+0x6a7/0x720 net/core/rtnetlink.c:7085
 netlink_rcv_skb+0x11e/0x220 net/netlink/af_netlink.c:2556
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:7103
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x5a7/0x680 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x5be/0x6f0 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:775 [inline]
 __sock_sendmsg net/socket.c:790 [inline]
 ____sys_sendmsg+0x532/0x580 net/socket.c:2684
 ___sys_sendmsg+0x195/0x1e0 net/socket.c:2738
 __sys_sendmsg net/socket.c:2770 [inline]
 __do_sys_sendmsg net/socket.c:2775 [inline]
 __se_sys_sendmsg net/socket.c:2773 [inline]
 __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2773
 x64_sys_call+0x194c/0x3020 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000000028ce -> 0x00000000000048ce

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 26602 Comm: syz.2.6300 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
==================================================================