syzbot

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BUG: KCSAN: data-race in try_to_compact_pages / try_to_compact_pages

read-write to 0xffff88823fffacf0 of 4 bytes by task 6757 on cpu 1:
 compaction_deferred mm/compaction.c:149 [inline]
 try_to_compact_pages+0x1be/0x940 mm/compaction.c:2838
 __alloc_pages_direct_compact+0x65/0x1d0 mm/page_alloc.c:4066
 __alloc_pages_slowpath+0x360/0x5f0 mm/page_alloc.c:4787
 __alloc_frozen_pages_noprof+0x270/0x360 mm/page_alloc.c:5161
 alloc_pages_mpol+0xb3/0x250 mm/mempolicy.c:2416
 alloc_frozen_pages_noprof+0x90/0x110 mm/mempolicy.c:2487
 ___kmalloc_large_node+0x52/0x100 mm/slub.c:4317
 __kmalloc_large_node_noprof+0x16/0xa0 mm/slub.c:4348
 __do_kmalloc_node mm/slub.c:4364 [inline]
 __kmalloc_noprof+0x2ab/0x3e0 mm/slub.c:4388
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kmalloc_array_noprof include/linux/slab.h:948 [inline]
 io_vec_realloc io_uring/rsrc.c:1327 [inline]
 io_import_reg_vec+0x645/0xe80 io_uring/rsrc.c:1520
 io_sendmsg_zc+0x91/0x550 io_uring/net.c:1545
 __io_issue_sqe+0xfb/0x2e0 io_uring/io_uring.c:1771
 io_issue_sqe+0x53/0x970 io_uring/io_uring.c:1794
 io_queue_sqe io_uring/io_uring.c:2023 [inline]
 io_submit_sqe io_uring/io_uring.c:2283 [inline]
 io_submit_sqes+0x675/0x1060 io_uring/io_uring.c:2396
 __do_sys_io_uring_enter io_uring/io_uring.c:3463 [inline]
 __se_sys_io_uring_enter+0x1c1/0x1b70 io_uring/io_uring.c:3397
 __x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3397
 x64_sys_call+0x2de1/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:427
 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

write to 0xffff88823fffacf0 of 4 bytes by task 6696 on cpu 0:
 compaction_deferred mm/compaction.c:150 [inline]
 try_to_compact_pages+0x207/0x940 mm/compaction.c:2838
 __alloc_pages_direct_compact+0x65/0x1d0 mm/page_alloc.c:4066
 __alloc_pages_slowpath+0x360/0x5f0 mm/page_alloc.c:4787
 __alloc_frozen_pages_noprof+0x270/0x360 mm/page_alloc.c:5161
 alloc_pages_mpol+0xb3/0x250 mm/mempolicy.c:2416
 alloc_frozen_pages_noprof+0x90/0x110 mm/mempolicy.c:2487
 ___kmalloc_large_node+0x52/0x100 mm/slub.c:4317
 __kmalloc_large_node_noprof+0x16/0xa0 mm/slub.c:4348
 __do_kmalloc_node mm/slub.c:4364 [inline]
 __kmalloc_noprof+0x2ab/0x3e0 mm/slub.c:4388
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kmalloc_array_noprof include/linux/slab.h:948 [inline]
 io_vec_realloc io_uring/rsrc.c:1327 [inline]
 io_import_reg_vec+0x645/0xe80 io_uring/rsrc.c:1520
 io_sendmsg_zc+0x91/0x550 io_uring/net.c:1545
 __io_issue_sqe+0xfb/0x2e0 io_uring/io_uring.c:1771
 io_issue_sqe+0x53/0x970 io_uring/io_uring.c:1794
 io_queue_sqe io_uring/io_uring.c:2023 [inline]
 io_submit_sqe io_uring/io_uring.c:2283 [inline]
 io_submit_sqes+0x675/0x1060 io_uring/io_uring.c:2396
 __do_sys_io_uring_enter io_uring/io_uring.c:3463 [inline]
 __se_sys_io_uring_enter+0x1c1/0x1b70 io_uring/io_uring.c:3397
 __x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3397
 x64_sys_call+0x2de1/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:427
 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: 0x00000005 -> 0x00000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 6696 Comm: syz.2.1234 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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