================================================================== BUG: KCSAN: data-race in data_alloc / prb_reserve write to 0xffffffff8686a980 of 8 bytes by task 37 on cpu 1: data_alloc+0x31c/0x390 kernel/printk/printk_ringbuffer.c:1130 prb_reserve+0x964/0xb60 kernel/printk/printk_ringbuffer.c:1724 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2302 vprintk_emit+0x15a/0x610 kernel/printk/printk.c:2402 vprintk_default+0x26/0x30 kernel/printk/printk.c:2441 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2451 bio_check_eod block/blk-core.c:565 [inline] submit_bio_noacct+0x8c8/0x9a0 block/blk-core.c:801 submit_bio+0x2a6/0x2c0 block/blk-core.c:921 submit_bh_wbc+0x2e0/0x320 fs/buffer.c:2824 submit_bh+0x1e/0x30 fs/buffer.c:2829 ext4_commit_super+0x1ac/0x280 fs/ext4/super.c:6275 ext4_handle_error+0x452/0x550 fs/ext4/super.c:718 __ext4_error_inode+0x1e3/0x3f0 fs/ext4/super.c:861 __ext4_mark_inode_dirty+0xbd/0x3f0 fs/ext4/inode.c:6476 __ext4_ext_dirty+0xdb/0x1f0 fs/ext4/extents.c:206 ext4_split_extent_at+0x48c/0x990 fs/ext4/extents.c:3230 ext4_split_extent+0x1af/0x3b0 fs/ext4/extents.c:3406 ext4_split_convert_extents fs/ext4/extents.c:3743 [inline] ext4_ext_handle_unwritten_extents fs/ext4/extents.c:3915 [inline] ext4_ext_map_blocks+0xb58/0x38a0 fs/ext4/extents.c:4274 ext4_map_create_blocks fs/ext4/inode.c:613 [inline] ext4_map_blocks+0x626/0xd20 fs/ext4/inode.c:816 mpage_map_one_extent fs/ext4/inode.c:2380 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2474 [inline] ext4_do_writepages+0x15ef/0x27e0 fs/ext4/inode.c:2932 ext4_writepages+0x179/0x300 fs/ext4/inode.c:3026 do_writepages+0x1c6/0x310 mm/page-writeback.c:2598 __writeback_single_inode+0x80/0x7c0 fs/fs-writeback.c:1737 writeback_sb_inodes+0x4b0/0xb20 fs/fs-writeback.c:2030 wb_writeback+0x252/0x5c0 fs/fs-writeback.c:2216 wb_do_writeback fs/fs-writeback.c:2363 [inline] wb_workfn+0x194/0x910 fs/fs-writeback.c:2403 process_one_work kernel/workqueue.c:3257 [inline] process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340 worker_thread+0x582/0x770 kernel/workqueue.c:3421 kthread+0x489/0x510 kernel/kthread.c:463 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 read to 0xffffffff8686a980 of 8 bytes by task 24001 on cpu 0: desc_read kernel/printk/printk_ringbuffer.c:496 [inline] desc_push_tail kernel/printk/printk_ringbuffer.c:792 [inline] desc_reserve kernel/printk/printk_ringbuffer.c:938 [inline] prb_reserve+0x249/0xb60 kernel/printk/printk_ringbuffer.c:1674 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2302 vprintk_emit+0x15a/0x610 kernel/printk/printk.c:2402 vprintk_default+0x26/0x30 kernel/printk/printk.c:2441 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2451 chnl_net_open+0x4d1/0x530 net/caif/chnl_net.c:-1 __dev_open+0x317/0x560 net/core/dev.c:1683 __dev_change_flags+0x147/0x3c0 net/core/dev.c:9734 netif_change_flags+0x5a/0xd0 net/core/dev.c:9797 do_setlink+0x8db/0x2780 net/core/rtnetlink.c:3158 rtnl_group_changelink net/core/rtnetlink.c:3790 [inline] __rtnl_newlink net/core/rtnetlink.c:3944 [inline] rtnl_newlink+0xdb5/0x1360 net/core/rtnetlink.c:4072 rtnetlink_rcv_msg+0x5fe/0x6d0 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2550 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6985 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5c0/0x690 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x145/0x180 net/socket.c:742 ____sys_sendmsg+0x31e/0x4a0 net/socket.c:2592 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2681 x64_sys_call+0x17ba/0x3000 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd8/0x2c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0xfffffffffffc7300 -> 0x000000000007f390 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 24001 Comm: syz.5.8130 Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 ================================================================== 1ªX¹¦À: entered promiscuous mode 1ªX¹¦À: entered allmulticast mode A link change request failed with some changes committed already. Interface 61ªX¹¦À may have been left with an inconsistent configuration, please check.