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

write to 0xffffffff88bceb34 of 1 bytes by task 6563 on cpu 0:
 string_nocheck lib/vsprintf.c:650 [inline]
 string+0x16c/0x210 lib/vsprintf.c:728
 vsnprintf+0xa09/0xe30 lib/vsprintf.c:2848
 vscnprintf+0x42/0x90 lib/vsprintf.c:2954
 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+0x75/0x80 kernel/printk/printk_safe.c:86
 _printk+0x7a/0xa0 kernel/printk/printk.c:2457
 batadv_hardif_enable_interface+0x507/0x640 net/batman-adv/hard-interface.c:756
 batadv_softif_slave_add+0x62/0xd0 net/batman-adv/soft-interface.c:844
 do_set_master net/core/rtnetlink.c:2917 [inline]
 do_setlink+0x7fb/0x22c0 net/core/rtnetlink.c:3116
 rtnl_changelink net/core/rtnetlink.c:3723 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3875 [inline]
 rtnl_newlink+0xde9/0x1250 net/core/rtnetlink.c:4012
 rtnetlink_rcv_msg+0x651/0x710 net/core/rtnetlink.c:6922
 netlink_rcv_skb+0x12c/0x230 net/netlink/af_netlink.c:2542
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6949
 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
 netlink_unicast+0x599/0x670 net/netlink/af_netlink.c:1347
 netlink_sendmsg+0x5cc/0x6e0 net/netlink/af_netlink.c:1891
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg+0x140/0x180 net/socket.c:726
 ____sys_sendmsg+0x312/0x410 net/socket.c:2583
 ___sys_sendmsg net/socket.c:2637 [inline]
 __sys_sendmsg+0x19d/0x230 net/socket.c:2669
 __do_sys_sendmsg net/socket.c:2674 [inline]
 __se_sys_sendmsg net/socket.c:2672 [inline]
 __x64_sys_sendmsg+0x46/0x50 net/socket.c:2672
 x64_sys_call+0x2734/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:47
 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

read to 0xffffffff88bceb30 of 8 bytes by task 6561 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_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1054
 prb_reserve+0x85e/0xb60 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x558/0x870 kernel/printk/printk.c:2326
 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2408
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:86
 _printk+0x7a/0xa0 kernel/printk/printk.c:2457
 __ext4_msg+0x18e/0x1a0 fs/ext4/super.c:998
 ext4_check_descriptors fs/ext4/super.c:3307 [inline]
 ext4_group_desc_init+0xb71/0x1400 fs/ext4/super.c:4899
 __ext4_fill_super fs/ext4/super.c:5339 [inline]
 ext4_fill_super+0x23c5/0x3a10 fs/ext4/super.c:5733
 get_tree_bdev_flags+0x29f/0x310 fs/super.c:1636
 get_tree_bdev+0x1f/0x30 fs/super.c:1659
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5765
 vfs_get_tree+0x56/0x1e0 fs/super.c:1814
 do_new_mount+0x227/0x690 fs/namespace.c:3511
 path_mount+0x49b/0xb30 fs/namespace.c:3838
 do_mount fs/namespace.c:3851 [inline]
 __do_sys_mount fs/namespace.c:4061 [inline]
 __se_sys_mount+0x27c/0x2d0 fs/namespace.c:4038
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4038
 x64_sys_call+0x2c84/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:166
 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: 0x000000010000190c -> 0x20306d6165742065

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 6561 Comm: syz.5.12542 Not tainted 6.13.0-rc6-syzkaller-00262-gb62cef9a5c67 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================
EXT4-fs (loop5): ext4_check_descriptors: Checksum for group 0 failed (14919!=20869)
EXT4-fs (loop5): stripe (65535) is not aligned with cluster size (16), stripe is disabled
EXT4-fs (loop5): invalid journal inode
EXT4-fs (loop5): can't get journal size
EXT4-fs error (device loop5): ext4_protect_reserved_inode:182: inode #3: comm syz.5.12542: blocks 2-2 from inode overlap system zone
EXT4-fs (loop5): failed to initialize system zone (-117)
EXT4-fs (loop5): mount failed