syzbot

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BUG: KCSAN: data-race in __delete_from_swap_cache / folio_mapping

write to 0xffffea00042cbf68 of 8 bytes by task 59 on cpu 1:
 __delete_from_swap_cache+0x1e8/0x280 mm/swap_state.c:161
 delete_from_swap_cache+0x73/0xe0 mm/swap_state.c:180
 shmem_swapin_folio+0xd82/0xe40 mm/shmem.c:2397
 shmem_get_folio_gfp+0x26c/0xd60 mm/shmem.c:2465
 shmem_get_folio mm/shmem.c:2638 [inline]
 shmem_write_begin+0xa8/0x190 mm/shmem.c:3288
 generic_perform_write+0x181/0x490 mm/filemap.c:4112
 shmem_file_write_iter+0xc5/0xf0 mm/shmem.c:3463
 lo_rw_aio+0x5fa/0x7c0 drivers/block/loop.c:-1
 do_req_filebacked drivers/block/loop.c:-1 [inline]
 loop_handle_cmd drivers/block/loop.c:1886 [inline]
 loop_process_work+0x52d/0xa60 drivers/block/loop.c:1921
 loop_rootcg_workfn+0x22/0x30 drivers/block/loop.c:1952
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3321
 worker_thread+0x582/0x770 kernel/workqueue.c:3402
 kthread+0x486/0x510 kernel/kthread.c:464
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffea00042cbf68 of 8 bytes by task 3600 on cpu 0:
 folio_mapping+0xdd/0x120 mm/util.c:699
 folio_evictable mm/internal.h:478 [inline]
 sort_folio mm/vmscan.c:4469 [inline]
 scan_folios mm/vmscan.c:4595 [inline]
 isolate_folios mm/vmscan.c:4690 [inline]
 evict_folios+0xdb9/0x33d0 mm/vmscan.c:4719
 try_to_shrink_lruvec+0x45a/0x7e0 mm/vmscan.c:4892
 lru_gen_shrink_lruvec mm/vmscan.c:5041 [inline]
 shrink_lruvec+0x22e/0x1b40 mm/vmscan.c:5797
 shrink_node_memcgs mm/vmscan.c:6033 [inline]
 shrink_node+0x686/0x2120 mm/vmscan.c:6074
 shrink_zones mm/vmscan.c:6318 [inline]
 do_try_to_free_pages+0x3f6/0xcd0 mm/vmscan.c:6380
 try_to_free_mem_cgroup_pages+0x1ab/0x410 mm/vmscan.c:6708
 try_charge_memcg+0x358/0x9e0 mm/memcontrol.c:2362
 obj_cgroup_charge_pages+0xa6/0x150 mm/memcontrol.c:2803
 __memcg_kmem_charge_page+0x9f/0x170 mm/memcontrol.c:2847
 __alloc_frozen_pages_noprof+0x188/0x360 mm/page_alloc.c:4976
 alloc_pages_mpol+0xb3/0x250 mm/mempolicy.c:2419
 alloc_frozen_pages_noprof mm/mempolicy.c:2490 [inline]
 alloc_pages_noprof+0x90/0x130 mm/mempolicy.c:2510
 vm_area_alloc_pages mm/vmalloc.c:3634 [inline]
 __vmalloc_area_node mm/vmalloc.c:3712 [inline]
 __vmalloc_node_range_noprof+0x6f2/0xe00 mm/vmalloc.c:3885
 __kvmalloc_node_noprof+0x30f/0x4e0 mm/slub.c:5037
 ip_set_alloc+0x1f/0x30 net/netfilter/ipset/ip_set_core.c:261
 hash_netiface_create+0x282/0x740 net/netfilter/ipset/ip_set_hash_gen.h:1568
 ip_set_create+0x3c9/0x960 net/netfilter/ipset/ip_set_core.c:1109
 nfnetlink_rcv_msg+0x4c6/0x590 net/netfilter/nfnetlink.c:303
 netlink_rcv_skb+0x123/0x220 net/netlink/af_netlink.c:2534
 nfnetlink_rcv+0x16b/0x1690 net/netfilter/nfnetlink.c:668
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x59e/0x670 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x145/0x180 net/socket.c:727
 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2566
 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2620
 __sys_sendmsg net/socket.c:2652 [inline]
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2655
 x64_sys_call+0x2999/0x2fb0 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

value changed: 0x00000000000002b8 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3600 Comm: syz.3.32 Not tainted 6.15.0-syzkaller-12426-ge271ed52b344 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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syz.3.32 (3600) used greatest stack depth: 6456 bytes left