==================================================================
BUG: KCSAN: data-race in data_push_tail / string

write to 0xffffffff88bf5f98 of 1 bytes by task 29 on cpu 0:
 string_nocheck lib/vsprintf.c:636 [inline]
 string+0x17f/0x210 lib/vsprintf.c:714
 vsnprintf+0x537/0x890 lib/vsprintf.c:2843
 vscnprintf+0x42/0x90 lib/vsprintf.c:2908
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216
 vprintk_store+0x589/0x870 kernel/printk/printk.c:2336
 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2408
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7a/0xa0 kernel/printk/printk.c:2457
 kauditd_printk_skb kernel/audit.c:546 [inline]
 kauditd_hold_skb+0x1a3/0x1b0 kernel/audit.c:581
 kauditd_send_queue+0x288/0x2e0 kernel/audit.c:766
 kauditd_thread+0x42a/0x650 kernel/audit.c:890
 kthread+0x4ae/0x520 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffffffff88bf5f98 of 8 bytes by task 13798 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:679
 data_realloc kernel/printk/printk_ringbuffer.c:1143 [inline]
 prb_reserve_in_last+0x773/0xc10 kernel/printk/printk_ringbuffer.c:1440
 vprintk_store+0x47b/0x870 kernel/printk/printk.c:2300
 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2408
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7a/0xa0 kernel/printk/printk.c:2457
 __ext4_grp_locked_error+0x5b0/0x7b0 fs/ext4/super.c:1071
 ext4_mb_generate_buddy+0x247/0x2d0 fs/ext4/mballoc.c:1217
 ext4_mb_init_cache+0x848/0xbc0 fs/ext4/mballoc.c:1406
 ext4_mb_init_group+0x210/0x3b0 fs/ext4/mballoc.c:1543
 ext4_mb_good_group_nolock fs/ext4/mballoc.c:2704 [inline]
 ext4_mb_regular_allocator+0xc2a/0x23a0 fs/ext4/mballoc.c:2903
 ext4_mb_new_blocks+0x801/0x2020 fs/ext4/mballoc.c:6217
 ext4_ext_map_blocks+0x1008/0x35c0 fs/ext4/extents.c:4379
 ext4_map_create_blocks fs/ext4/inode.c:516 [inline]
 ext4_map_blocks+0x5aa/0xd20 fs/ext4/inode.c:702
 mpage_map_one_extent fs/ext4/inode.c:2219 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2272 [inline]
 ext4_do_writepages+0x14c3/0x2130 fs/ext4/inode.c:2735
 ext4_writepages+0x159/0x2e0 fs/ext4/inode.c:2824
 do_writepages+0x1d8/0x480 mm/page-writeback.c:2687
 filemap_fdatawrite_wbc mm/filemap.c:389 [inline]
 __filemap_fdatawrite_range mm/filemap.c:422 [inline]
 file_write_and_wait_range+0x168/0x2f0 mm/filemap.c:797
 generic_buffers_fsync_noflush+0x46/0x120 fs/buffer.c:600
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x1ff/0x6c0 fs/ext4/fsync.c:151
 vfs_fsync_range fs/sync.c:187 [inline]
 vfs_fsync fs/sync.c:201 [inline]
 do_fsync fs/sync.c:212 [inline]
 __do_sys_fdatasync fs/sync.c:222 [inline]
 __se_sys_fdatasync fs/sync.c:220 [inline]
 __x64_sys_fdatasync+0x7e/0xd0 fs/sync.c:220
 x64_sys_call+0x15e1/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:76
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000100007368 -> 0x7561203a29383633

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 13798 Comm: syz.7.25734 Not tainted 6.13.0-syzkaller-09793-g69b8923f5003 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
==================================================================
block bitmap and bg descriptor inconsistent: 0 vs 150994969 free clusters
EXT4-fs (loop7): Delayed block allocation failed for inode 18 at logical offset 0 with max blocks 1222 with error 28
EXT4-fs (loop7): This should not happen!! Data will be lost

EXT4-fs (loop7): Total free blocks count 0
EXT4-fs (loop7): Free/Dirty block details
EXT4-fs (loop7): free_blocks=2415919504
EXT4-fs (loop7): dirty_blocks=1280
EXT4-fs (loop7): Block reservation details
EXT4-fs (loop7): i_reserved_data_blocks=80