syzbot

EXT4-fs (loop4): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
==================================================================
BUG: KCSAN: data-race in vmalloc_info_show / vmalloc_info_show

write to 0xffff88810100e218 of 4 bytes by task 3846 on cpu 0:
 show_numa_info mm/vmalloc.c:4948 [inline]
 vmalloc_info_show+0x421/0x790 mm/vmalloc.c:5033
 seq_read_iter+0x316/0x940 fs/seq_file.c:230
 proc_reg_read_iter+0x10d/0x180 fs/proc/inode.c:299
 new_sync_read fs/read_write.c:489 [inline]
 vfs_read+0x5ca/0x6f0 fs/read_write.c:570
 ksys_read+0xda/0x1a0 fs/read_write.c:713
 __do_sys_read fs/read_write.c:722 [inline]
 __se_sys_read fs/read_write.c:720 [inline]
 __x64_sys_read+0x40/0x50 fs/read_write.c:720
 x64_sys_call+0x2d77/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read-write to 0xffff88810100e218 of 4 bytes by task 3844 on cpu 1:
 show_numa_info mm/vmalloc.c:4951 [inline]
 vmalloc_info_show+0x481/0x790 mm/vmalloc.c:5033
 seq_read_iter+0x316/0x940 fs/seq_file.c:230
 proc_reg_read_iter+0x10d/0x180 fs/proc/inode.c:299
 new_sync_read fs/read_write.c:489 [inline]
 vfs_read+0x5ca/0x6f0 fs/read_write.c:570
 ksys_read+0xda/0x1a0 fs/read_write.c:713
 __do_sys_read fs/read_write.c:722 [inline]
 __se_sys_read fs/read_write.c:720 [inline]
 __x64_sys_read+0x40/0x50 fs/read_write.c:720
 x64_sys_call+0x2d77/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000048 -> 0x00000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3844 Comm: syz.4.124 Not tainted 6.15.0-rc5-syzkaller-00353-gcd802e7e5f1e #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
==================================================================