loop0: detected capacity change from 0 to 128 ================================================================== BUG: KCSAN: data-race in data_push_tail / string write to 0xffffffff88e25e00 of 1 bytes by task 22498 on cpu 1: string_nocheck lib/vsprintf.c:657 [inline] string+0x187/0x220 lib/vsprintf.c:735 vsnprintf+0x532/0x890 lib/vsprintf.c:2926 vscnprintf+0x41/0x90 lib/vsprintf.c:2991 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 __netdev_printk+0x321/0x3e0 net/core/dev.c:12596 netdev_info+0x9b/0xd0 net/core/dev.c:12643 __dev_set_promiscuity+0x233/0x450 net/core/dev.c:9352 netif_set_promiscuity+0x39/0x90 net/core/dev.c:9387 dev_set_promiscuity+0xc1/0x170 net/core/dev_api.c:287 nbp_delete_promisc net/bridge/br_if.c:254 [inline] del_nbp+0xc7/0x790 net/bridge/br_if.c:340 br_del_if+0x99/0x1e0 net/bridge/br_if.c:740 br_del_slave+0x24/0x30 net/bridge/br_device.c:382 do_set_master+0x227/0x460 net/core/rtnetlink.c:2932 do_setlink+0xa43/0x2810 net/core/rtnetlink.c:3150 rtnl_group_changelink net/core/rtnetlink.c:3775 [inline] __rtnl_newlink net/core/rtnetlink.c:3929 [inline] rtnl_newlink+0xd8b/0x12d0 net/core/rtnetlink.c:4057 rtnetlink_rcv_msg+0x5fb/0x6d0 net/core/rtnetlink.c:6946 netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2552 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6973 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5bd/0x690 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg+0x142/0x180 net/socket.c:729 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2614 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2668 __sys_sendmsg net/socket.c:2700 [inline] __do_sys_sendmsg net/socket.c:2705 [inline] __se_sys_sendmsg net/socket.c:2703 [inline] __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2703 x64_sys_call+0x191e/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffffffff88e25e00 of 8 bytes by task 22501 on cpu 0: 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 set_capacity_and_notify+0x14c/0x1f0 block/genhd.c:93 loop_set_size+0x2e/0x70 drivers/block/loop.c:210 loop_configure+0x8d3/0xa50 drivers/block/loop.c:1067 lo_ioctl+0x1e1/0x1350 drivers/block/loop.c:1523 blkdev_ioctl+0x352/0x440 block/ioctl.c:705 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:598 [inline] __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:584 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:584 x64_sys_call+0x1816/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x000000010000085c -> 0x735f656764697262 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 22501 Comm: syz.0.6225 Tainted: G W 6.16.0-syzkaller-11852-g479058002c32 #0 PREEMPT(voluntary) Tainted: [W]=WARN Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 ================================================================== bio_check_eod: 34465 callbacks suppressed syz.0.6225: attempt to access beyond end of device loop0: rw=2049, sector=145, nr_sectors = 16 limit=128 syz.0.6225: attempt to access beyond end of device loop0: rw=2049, sector=169, nr_sectors = 24 limit=128 syz.0.6225: attempt to access beyond end of device loop0: rw=2049, sector=201, nr_sectors = 8 limit=128 syz.0.6225: attempt to access beyond end of device loop0: rw=2049, sector=217, nr_sectors = 8 limit=128 syz.0.6225: attempt to access beyond end of device loop0: rw=2049, sector=233, nr_sectors = 8 limit=128 syz.0.6225: attempt to access beyond end of device loop0: rw=2049, sector=249, nr_sectors = 8 limit=128 syz.0.6225: attempt to access beyond end of device loop0: rw=2049, sector=265, nr_sectors = 8 limit=128 syz.0.6225: attempt to access beyond end of device loop0: rw=2049, sector=281, nr_sectors = 9 limit=128