sch_tbf: burst 3092 is lower than device lo mtu (65550) ! EXT4-fs error (device loop0): ext4_mb_generate_buddy:1220: group 0, ================================================================== BUG: KCSAN: data-race in data_push_tail / vsnprintf write to 0xffffffff88e1c57c of 53 bytes by task 6924 on cpu 0: vsnprintf+0x2ce/0x890 lib/vsprintf.c:2804 vscnprintf+0x41/0x90 lib/vsprintf.c:2917 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216 vprintk_store+0x599/0x860 kernel/printk/printk.c:2336 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2475 __nla_validate_parse+0x1738/0x1d00 lib/nlattr.c:647 __nla_parse+0x40/0x60 lib/nlattr.c:732 __nlmsg_parse include/net/netlink.h:765 [inline] nlmsg_parse_deprecated include/net/netlink.h:806 [inline] tc_dump_qdisc+0x175/0x710 net/sched/sch_api.c:1897 rtnl_dumpit+0x6e/0x140 net/core/rtnetlink.c:6824 netlink_dump+0x38c/0x7f0 net/netlink/af_netlink.c:2309 __netlink_dump_start+0x43e/0x520 net/netlink/af_netlink.c:2424 netlink_dump_start include/linux/netlink.h:340 [inline] rtnetlink_dump_start net/core/rtnetlink.c:6853 [inline] rtnetlink_rcv_msg+0x552/0x6d0 net/core/rtnetlink.c:6920 netlink_rcv_skb+0x120/0x220 net/netlink/af_netlink.c:2534 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6982 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x59e/0x670 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x142/0x180 net/socket.c:727 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2566 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2620 __sys_sendmsg net/socket.c:2652 [inline] __do_sys_sendmsg net/socket.c:2657 [inline] __se_sys_sendmsg net/socket.c:2655 [inline] __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2655 x64_sys_call+0x2999/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffffffff88e1c580 of 8 bytes by task 6926 on cpu 1: data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline] data_push_tail+0xfd/0x420 kernel/printk/printk_ringbuffer.c:679 data_alloc+0xbf/0x2b0 kernel/printk/printk_ringbuffer.c:1054 prb_reserve+0x808/0xaf0 kernel/printk/printk_ringbuffer.c:1669 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2326 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2475 __ext4_grp_locked_error+0x52a/0x780 fs/ext4/super.c:1051 ext4_mb_generate_buddy+0x243/0x2c0 fs/ext4/mballoc.c:1217 ext4_mb_init_cache+0x81b/0xb60 fs/ext4/mballoc.c:1406 ext4_mb_init_group+0x223/0x3b0 fs/ext4/mballoc.c:1543 ext4_mb_load_buddy_gfp+0x6ed/0x750 fs/ext4/mballoc.c:1613 ext4_mb_load_buddy fs/ext4/mballoc.c:1733 [inline] ext4_mb_find_by_goal+0x10b/0x720 fs/ext4/mballoc.c:2346 ext4_mb_regular_allocator+0x135/0x2300 fs/ext4/mballoc.c:2818 ext4_mb_new_blocks+0x800/0x2050 fs/ext4/mballoc.c:6215 ext4_ext_map_blocks+0xfe6/0x3620 fs/ext4/extents.c:4379 ext4_map_create_blocks fs/ext4/inode.c:520 [inline] ext4_map_blocks+0x5ab/0xd00 fs/ext4/inode.c:706 mpage_map_one_extent fs/ext4/inode.c:2224 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2277 [inline] ext4_do_writepages+0x13dc/0x2270 fs/ext4/inode.c:2739 ext4_writepages+0x176/0x300 fs/ext4/inode.c:2829 do_writepages+0x1d2/0x480 mm/page-writeback.c:2656 filemap_fdatawrite_wbc mm/filemap.c:386 [inline] __filemap_fdatawrite_range mm/filemap.c:419 [inline] file_write_and_wait_range+0x156/0x2c0 mm/filemap.c:794 generic_buffers_fsync_noflush+0x45/0x120 fs/buffer.c:611 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline] ext4_sync_file+0x1ab/0x690 fs/ext4/fsync.c:147 vfs_fsync_range+0x10a/0x130 fs/sync.c:187 generic_write_sync include/linux/fs.h:2976 [inline] ext4_buffered_write_iter+0x34f/0x3c0 fs/ext4/file.c:305 ext4_file_write_iter+0x383/0xf00 fs/ext4/file.c:-1 do_iter_readv_writev+0x41e/0x4c0 fs/read_write.c:-1 vfs_writev+0x2c9/0x870 fs/read_write.c:1055 do_pwritev fs/read_write.c:1151 [inline] __do_sys_pwritev2 fs/read_write.c:1209 [inline] __se_sys_pwritev2+0xfc/0x1c0 fs/read_write.c:1200 __x64_sys_pwritev2+0x67/0x80 fs/read_write.c:1200 x64_sys_call+0x1cea/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:329 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x00000000ffffe3d5 -> 0x65766f7466656c20 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 6926 Comm: syz.0.1136 Not tainted 6.15.0-rc4-syzkaller-00052-g4f79eaa2ceac #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 ================================================================== block bitmap and bg descriptor inconsistent: 25 vs 4128793 free clusters EXT4-fs (loop0): Delayed block allocation failed for inode 16 at logical offset 16 with max blocks 17 with error 28 EXT4-fs (loop0): This should not happen!! Data will be lost EXT4-fs (loop0): Total free blocks count 0 EXT4-fs (loop0): Free/Dirty block details EXT4-fs (loop0): free_blocks=66060288 EXT4-fs (loop0): dirty_blocks=32 EXT4-fs (loop0): Block reservation details EXT4-fs (loop0): i_reserved_data_blocks=2 syz.0.1136 (6926) used greatest stack depth: 7048 bytes left