==================================================================
BUG: KCSAN: data-race in relay_switch_subbuf / relay_switch_subbuf

write to 0xffff88813c3b1c38 of 8 bytes by task 2738 on cpu 0:
 relay_switch_subbuf+0x399/0x3a0 kernel/relay.c:708
 relay_reserve include/linux/relay.h:248 [inline]
 __blk_add_trace+0x665/0x720 kernel/trace/blktrace.c:276
 blk_add_trace_bio kernel/trace/blktrace.c:903 [inline]
 blk_add_trace_bio_queue+0x12c/0x140 kernel/trace/blktrace.c:935
 trace_block_bio_queue include/trace/events/block.h:383 [inline]
 submit_bio_noacct_nocheck+0x57d/0x5e0 block/blk-core.c:699
 submit_bio_noacct+0x67d/0x830 block/blk-core.c:826
 submit_bio+0x212/0x220 block/blk-core.c:868
 submit_bh_wbc+0x2ca/0x310 fs/buffer.c:2800
 submit_bh+0x1c/0x20 fs/buffer.c:2805
 jbd2_journal_commit_transaction+0x15e7/0x33b0 fs/jbd2/commit.c:731
 kjournald2+0x242/0x420 fs/jbd2/journal.c:201
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

write to 0xffff88813c3b1c38 of 8 bytes by task 4415 on cpu 1:
 relay_switch_subbuf+0x399/0x3a0 kernel/relay.c:708
 relay_reserve include/linux/relay.h:248 [inline]
 __blk_add_trace+0x665/0x720 kernel/trace/blktrace.c:276
 blk_add_trace_bio kernel/trace/blktrace.c:903 [inline]
 blk_add_trace_bio_backmerge+0x12c/0x140 kernel/trace/blktrace.c:923
 trace_block_bio_backmerge include/trace/events/block.h:361 [inline]
 bio_attempt_back_merge+0x4af/0x510 block/blk-merge.c:981
 blk_attempt_bio_merge+0x43d/0x480 block/blk-merge.c:1064
 blk_attempt_plug_merge+0xb4/0xf0 block/blk-merge.c:1111
 blk_mq_attempt_bio_merge block/blk-mq.c:2874 [inline]
 blk_mq_get_new_requests block/blk-mq.c:2894 [inline]
 blk_mq_submit_bio+0x323/0xe30 block/blk-mq.c:3001
 __submit_bio+0x11c/0x350 block/blk-core.c:608
 __submit_bio_noacct_mq block/blk-core.c:687 [inline]
 submit_bio_noacct_nocheck+0x449/0x5e0 block/blk-core.c:716
 submit_bio_noacct+0x67d/0x830 block/blk-core.c:826
 submit_bio+0x212/0x220 block/blk-core.c:868
 swap_writepage_bdev_async mm/page_io.c:371 [inline]
 __swap_writepage+0x612/0xc40 mm/page_io.c:389
 swap_writepage+0xa9/0x150 mm/page_io.c:209
 pageout mm/vmscan.c:654 [inline]
 shrink_folio_list+0x196b/0x2570 mm/vmscan.c:1316
 shrink_inactive_list mm/vmscan.c:1914 [inline]
 shrink_list mm/vmscan.c:2155 [inline]
 shrink_lruvec+0xd80/0x17a0 mm/vmscan.c:5681
 shrink_node_memcgs mm/vmscan.c:5867 [inline]
 shrink_node+0xac3/0x15d0 mm/vmscan.c:5902
 shrink_zones mm/vmscan.c:6141 [inline]
 do_try_to_free_pages+0x43d/0xce0 mm/vmscan.c:6203
 try_to_free_mem_cgroup_pages+0x1e2/0x480 mm/vmscan.c:6518
 try_charge_memcg+0x280/0xd20 mm/memcontrol.c:2782
 obj_cgroup_charge_pages+0xbd/0x1c0 mm/memcontrol.c:3301
 __memcg_kmem_charge_page+0x9c/0x170 mm/memcontrol.c:3327
 __alloc_pages+0x1bb/0x340 mm/page_alloc.c:4584
 alloc_pages_mpol+0xb1/0x1d0 mm/mempolicy.c:2133
 alloc_pages+0xe0/0x100 mm/mempolicy.c:2204
 vm_area_alloc_pages mm/vmalloc.c:3063 [inline]
 __vmalloc_area_node mm/vmalloc.c:3139 [inline]
 __vmalloc_node_range+0x6ee/0xec0 mm/vmalloc.c:3320
 kvmalloc_node+0x121/0x170 mm/util.c:642
 kvmalloc include/linux/slab.h:728 [inline]
 xt_alloc_table_info+0x3d/0x80 net/netfilter/x_tables.c:1192
 do_replace net/ipv6/netfilter/ip6_tables.c:1139 [inline]
 do_ip6t_set_ctl+0x633/0x1800 net/ipv6/netfilter/ip6_tables.c:1636
 nf_setsockopt+0x18d/0x1b0 net/netfilter/nf_sockopt.c:101
 ipv6_setsockopt+0x11c/0x130 net/ipv6/ipv6_sockglue.c:997
 udpv6_setsockopt+0x95/0xa0 net/ipv6/udp.c:1694
 sock_common_setsockopt+0x61/0x70 net/core/sock.c:3716
 do_sock_setsockopt net/socket.c:2311 [inline]
 __sys_setsockopt+0x1d4/0x240 net/socket.c:2334
 __do_sys_setsockopt net/socket.c:2343 [inline]
 __se_sys_setsockopt net/socket.c:2340 [inline]
 __x64_sys_setsockopt+0x66/0x80 net/socket.c:2340
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000000030 -> 0x0000000000000040

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4415 Comm: syz-executor.3 Not tainted 6.8.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
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syz-executor.3 (4415) used greatest stack depth: 7912 bytes left