loop1: p1 < > p4
loop1: p4 size 8388608 extends beyond EOD, 
==================================================================
BUG: KCSAN: data-race in data_push_tail / string

write to 0xffffffff88e3f6f0 of 1 bytes by task 8414 on cpu 0:
 string_nocheck lib/vsprintf.c:643 [inline]
 string+0x17d/0x210 lib/vsprintf.c:721
 vsnprintf+0x539/0x8a0 lib/vsprintf.c:2852
 va_format lib/vsprintf.c:1715 [inline]
 pointer+0x849/0xcf0 lib/vsprintf.c:2474
 vsnprintf+0x48f/0x8a0 lib/vsprintf.c:2856
 vscnprintf+0x42/0x90 lib/vsprintf.c:2917
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216
 vprintk_store+0x583/0x860 kernel/printk/printk.c:2336
 vprintk_emit+0x1a0/0x6c0 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 kernel/printk/printk.c:2475
 __netdev_printk+0x2d1/0x3e0 net/core/dev.c:12400
 netdev_info+0x9e/0xd0 net/core/dev.c:12447
 netif_set_allmulti+0x15f/0x250 net/core/dev.c:9243
 dev_set_allmulti+0xd4/0x190 net/core/dev_api.c:289
 macvlan_change_rx_flags+0xac/0x150 drivers/net/macvlan.c:784
 dev_change_rx_flags net/core/dev.c:9143 [inline]
 netif_set_allmulti+0x191/0x250 net/core/dev.c:9245
 __dev_change_flags+0x32b/0x410 net/core/dev.c:9386
 rtnl_configure_link net/core/rtnetlink.c:3588 [inline]
 rtnl_newlink_create+0x36a/0x640 net/core/rtnetlink.c:3846
 __rtnl_newlink net/core/rtnetlink.c:3953 [inline]
 rtnl_newlink+0xf38/0x12d0 net/core/rtnetlink.c:4068
 rtnetlink_rcv_msg+0x65a/0x740 net/core/rtnetlink.c:6958
 netlink_rcv_skb+0x12f/0x230 net/netlink/af_netlink.c:2534
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6985
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x605/0x6c0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x609/0x720 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x140/0x180 net/socket.c:727
 ____sys_sendmsg+0x350/0x4e0 net/socket.c:2566
 ___sys_sendmsg net/socket.c:2620 [inline]
 __sys_sendmsg+0x1a0/0x240 net/socket.c:2652
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0x46/0x50 net/socket.c:2655
 x64_sys_call+0x26f3/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff88e3f6f0 of 8 bytes by task 8408 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0x107/0x440 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbd/0x2c0 kernel/printk/printk_ringbuffer.c:1054
 prb_reserve+0x86a/0xb80 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x552/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x1a0/0x6c0 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 kernel/printk/printk.c:2475
 blk_add_partition block/partitions/core.c:549 [inline]
 blk_add_partitions block/partitions/core.c:633 [inline]
 bdev_disk_changed+0x87a/0xcd0 block/partitions/core.c:693
 loop_reread_partitions drivers/block/loop.c:513 [inline]
 loop_set_status+0x531/0x5d0 drivers/block/loop.c:1319
 lo_ioctl+0x81a/0x1570 drivers/block/loop.c:-1
 blkdev_ioctl+0x35b/0x450 block/ioctl.c:698
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xc9/0x140 fs/ioctl.c:892
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:892
 x64_sys_call+0x168d/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000ffffe140 -> 0x746c756d6c6c6120

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 8408 Comm: syz.1.1975 Not tainted 6.15.0-rc1-syzkaller-00333-g5aaaedb0cb54 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================
truncated