================================================================== BUG: KCSAN: data-race in data_push_tail / vsnprintf write to 0xffffffff84532f1c of 1 bytes by task 12757 on cpu 1: vsnprintf+0xe8f/0xed0 lib/vsprintf.c:2824 vscnprintf+0x29/0x80 lib/vsprintf.c:2855 printk_sprint kernel/printk/printk.c:2012 [inline] vprintk_store+0x4c1/0x9c0 kernel/printk/printk.c:2115 vprintk_emit+0xca/0x3d0 kernel/printk/printk.c:2157 vprintk_default+0x22/0x30 kernel/printk/printk.c:2185 vprintk+0x15a/0x170 kernel/printk/printk_safe.c:392 printk+0x62/0x87 kernel/printk/printk.c:2216 disk_unlock_native_capacity block/partitions/core.c:531 [inline] blk_add_partition block/partitions/core.c:565 [inline] blk_add_partitions+0x712/0xa80 block/partitions/core.c:653 bdev_disk_changed+0x2a1/0x310 fs/block_dev.c:1271 loop_reread_partitions drivers/block/loop.c:656 [inline] loop_set_status+0x75f/0x7e0 drivers/block/loop.c:1419 lo_ioctl+0x758/0x11f0 drivers/block/loop.c:1487 blkdev_ioctl+0x1d0/0x3c0 block/ioctl.c:585 block_ioctl+0x6d/0x80 fs/block_dev.c:1664 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffffffff84532f18 of 8 bytes by task 12754 on cpu 0: data_make_reusable kernel/printk/printk_ringbuffer.c:587 [inline] data_push_tail+0x125/0x460 kernel/printk/printk_ringbuffer.c:672 data_alloc+0xbc/0x2b0 kernel/printk/printk_ringbuffer.c:1043 prb_reserve+0x8f0/0xbc0 kernel/printk/printk_ringbuffer.c:1549 vprintk_store+0x3e9/0x9c0 kernel/printk/printk.c:2105 vprintk_emit+0xca/0x3d0 kernel/printk/printk.c:2157 vprintk_default+0x22/0x30 kernel/printk/printk.c:2185 vprintk+0x15a/0x170 kernel/printk/printk_safe.c:392 printk+0x62/0x87 kernel/printk/printk.c:2216 blk_add_partition block/partitions/core.c:571 [inline] blk_add_partitions+0x686/0xa80 block/partitions/core.c:653 bdev_disk_changed+0x2a1/0x310 fs/block_dev.c:1271 loop_reread_partitions drivers/block/loop.c:656 [inline] loop_set_status+0x75f/0x7e0 drivers/block/loop.c:1419 lo_ioctl+0x758/0x11f0 drivers/block/loop.c:1487 blkdev_ioctl+0x1d0/0x3c0 block/ioctl.c:585 block_ioctl+0x6d/0x80 fs/block_dev.c:1664 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 12754 Comm: syz-executor.0 Tainted: G W 5.13.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================