================================================================== BUG: KCSAN: data-race in data_push_tail / number write to 0xffffffff883b26b4 of 1 bytes by task 13517 on cpu 1: number+0x7d0/0xa90 lib/vsprintf.c:564 vsnprintf+0xa44/0xe30 lib/vsprintf.c:2890 vscnprintf+0x42/0x90 lib/vsprintf.c:2930 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2165 vprintk_store+0x570/0x810 kernel/printk/printk.c:2279 vprintk_emit+0x10c/0x5e0 kernel/printk/printk.c:2329 vprintk_default+0x26/0x30 kernel/printk/printk.c:2363 vprintk+0x75/0x80 kernel/printk/printk_safe.c:45 _printk+0x7a/0xa0 kernel/printk/printk.c:2373 validate_nla lib/nlattr.c:414 [inline] __nla_validate_parse+0x126c/0x1ce0 lib/nlattr.c:635 __nla_parse+0x40/0x60 lib/nlattr.c:732 __nlmsg_parse include/net/netlink.h:756 [inline] nlmsg_parse_deprecated include/net/netlink.h:797 [inline] inet6_rtm_valid_getroute_req net/ipv6/route.c:5968 [inline] inet6_rtm_getroute+0x19a/0xc50 net/ipv6/route.c:6034 rtnetlink_rcv_msg+0x7d0/0x8e0 net/core/rtnetlink.c:6586 netlink_rcv_skb+0x12c/0x230 net/netlink/af_netlink.c:2559 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6613 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline] netlink_unicast+0x58d/0x660 net/netlink/af_netlink.c:1361 netlink_sendmsg+0x5d3/0x6e0 net/netlink/af_netlink.c:1905 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x140/0x180 net/socket.c:745 ____sys_sendmsg+0x312/0x410 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x1e9/0x280 net/socket.c:2667 __do_sys_sendmsg net/socket.c:2676 [inline] __se_sys_sendmsg net/socket.c:2674 [inline] __x64_sys_sendmsg+0x46/0x50 net/socket.c:2674 do_syscall_64+0xd3/0x1d0 entry_SYSCALL_64_after_hwframe+0x72/0x7a read to 0xffffffff883b26b0 of 8 bytes by task 1465 on cpu 0: data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline] data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:679 data_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1054 prb_reserve+0x85e/0xb60 kernel/printk/printk_ringbuffer.c:1669 vprintk_store+0x53f/0x810 kernel/printk/printk.c:2269 vprintk_emit+0x10c/0x5e0 kernel/printk/printk.c:2329 vprintk_default+0x26/0x30 kernel/printk/printk.c:2363 vprintk+0x75/0x80 kernel/printk/printk_safe.c:45 _printk+0x7a/0xa0 kernel/printk/printk.c:2373 __ext4_msg+0x18e/0x1a0 fs/ext4/super.c:1006 ext4_print_free_blocks+0x152/0x190 fs/ext4/inode.c:1617 mpage_map_and_submit_extent fs/ext4/inode.c:2244 [inline] ext4_do_writepages+0x19db/0x2110 fs/ext4/inode.c:2679 ext4_writepages+0x159/0x2e0 fs/ext4/inode.c:2768 do_writepages+0x1d8/0x480 mm/page-writeback.c:2612 __writeback_single_inode+0x91/0x870 fs/fs-writeback.c:1650 writeback_sb_inodes+0x4de/0xaa0 fs/fs-writeback.c:1941 wb_writeback+0x252/0x6f0 fs/fs-writeback.c:2117 wb_do_writeback fs/fs-writeback.c:2264 [inline] wb_workfn+0x1a8/0x940 fs/fs-writeback.c:2304 process_one_work kernel/workqueue.c:3254 [inline] process_scheduled_works+0x465/0x990 kernel/workqueue.c:3335 worker_thread+0x526/0x730 kernel/workqueue.c:3416 kthread+0x1d1/0x210 kernel/kthread.c:388 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 value changed: 0x00000000ffffe190 -> 0x0000000020657079 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 1465 Comm: kworker/u8:5 Tainted: G W 6.9.0-rc3-syzkaller-00011-g20cb38a7af88 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Workqueue: writeback wb_workfn (flush-7:2) ================================================================== EXT4-fs (loop2): i_reserved_data_blocks=1