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BUG: KCSAN: data-race in data_push_tail / number

write to 0xffffffff8452167f of 1 bytes by task 6785 on cpu 1:
 number+0x836/0xb50 lib/vsprintf.c:529
 vsnprintf+0xb6d/0xed0 lib/vsprintf.c:2818
 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
 set_capacity_and_notify+0x15a/0x1c0 block/genhd.c:73
 loop_set_size drivers/block/loop.c:255 [inline]
 loop_configure+0xafc/0xcb0 drivers/block/loop.c:1162
 lo_ioctl+0x555/0x11f0 drivers/block/loop.c:1690
 blkdev_ioctl+0x1d0/0x3c0 block/ioctl.c:585
 block_ioctl+0x6d/0x80 fs/block_dev.c:1662
 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 0xffffffff84521678 of 8 bytes by task 6786 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
 ref_ctr_mismatch_warn kernel/events/uprobes.c:719 [inline]
 alloc_uprobe kernel/events/uprobes.c:746 [inline]
 __uprobe_register+0x6d7/0x8a0 kernel/events/uprobes.c:1167
 uprobe_register_refctr+0x29/0x40 kernel/events/uprobes.c:1203
 trace_uprobe_enable kernel/trace/trace_uprobe.c:1065 [inline]
 probe_event_enable+0x2be/0x7d0 kernel/trace/trace_uprobe.c:1134
 trace_uprobe_register+0x88/0x410 kernel/trace/trace_uprobe.c:1461
 perf_trace_event_reg kernel/trace/trace_event_perf.c:129 [inline]
 perf_trace_event_init+0x34e/0x790 kernel/trace/trace_event_perf.c:204
 perf_uprobe_init+0xf5/0x140 kernel/trace/trace_event_perf.c:336
 perf_uprobe_event_init+0xde/0x140 kernel/events/core.c:9870
 perf_try_init_event+0x21a/0x400 kernel/events/core.c:11187
 perf_init_event kernel/events/core.c:11251 [inline]
 perf_event_alloc+0xa60/0x1790 kernel/events/core.c:11542
 __do_sys_perf_event_open kernel/events/core.c:12031 [inline]
 __se_sys_perf_event_open+0x5c7/0x2740 kernel/events/core.c:11923
 __x64_sys_perf_event_open+0x63/0x70 kernel/events/core.c:11923
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000001000023d4 -> 0x742030206d6f7266

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6786 Comm: syz-executor.1 Not tainted 5.13.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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