KCSAN: data-race in get_tree_bdev_flags / super_cache

Kernel	Title	Rank 🛈	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in get_tree_bdev_flags / super_cache_count ext4	6				1	147d	147d	0/29	auto-obsoleted due to no activity on 2025/04/12 12:24
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BUG: KCSAN: data-race in get_tree_bdev_flags / super_cache_count

read-write to 0xffff88812b9f5050 of 8 bytes by task 4292 on cpu 1:
 get_tree_bdev_flags+0x2e4/0x300 fs/super.c:1686
 get_tree_bdev+0x1f/0x30 fs/super.c:1704
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5756
 vfs_get_tree+0x54/0x1d0 fs/super.c:1804
 do_new_mount+0x207/0x680 fs/namespace.c:3902
 path_mount+0x4a4/0xb20 fs/namespace.c:4226
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4427
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4427
 x64_sys_call+0xd36/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:166
 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

read to 0xffff88812b9f5050 of 8 bytes by task 4296 on cpu 0:
 super_cache_count+0x30/0x160 fs/super.c:257
 do_shrink_slab+0x60/0x680 mm/shrinker.c:384
 shrink_slab_memcg mm/shrinker.c:550 [inline]
 shrink_slab+0x448/0x760 mm/shrinker.c:628
 shrink_node_memcgs mm/vmscan.c:6035 [inline]
 shrink_node+0x6c3/0x2120 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+0x120/0x220 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+0x5a1/0x670 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: 0x0000000010810050 -> 0x0000000070810050

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 4296 Comm: syz.5.232 Not tainted 6.16.0-rc4-syzkaller-00123-g4c06e63b9203 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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