syzbot

==================================================================
BUG: KCSAN: data-race in mem_cgroup_flush_stats_ratelimited / tick_do_update_jiffies64

read-write to 0xffffffff86c07a00 of 8 bytes by interrupt on cpu 1:
 tick_do_update_jiffies64+0x113/0x1c0 kernel/time/tick-sched.c:118
 tick_sched_do_timer kernel/time/tick-sched.c:253 [inline]
 tick_nohz_handler+0x8d/0x3d0 kernel/time/tick-sched.c:312
 __run_hrtimer kernel/time/hrtimer.c:1930 [inline]
 __hrtimer_run_queues+0x276/0x4f0 kernel/time/hrtimer.c:1994
 hrtimer_interrupt+0x261/0x850 kernel/time/hrtimer.c:2113
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1067
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1061
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
 get_ctx kernel/kcsan/core.c:206 [inline]
 check_access kernel/kcsan/core.c:750 [inline]
 __tsan_read8+0xe5/0x190 kernel/kcsan/core.c:1025
 bio_associate_blkg_from_css+0x1ca/0x6b0 block/blk-cgroup.c:2149
 bio_associate_blkg+0xc1/0xd0 block/blk-cgroup.c:2177
 bio_init block/bio.c:239 [inline]
 bio_alloc_bioset+0x533/0x640 block/bio.c:605
 bio_alloc include/linux/bio.h:367 [inline]
 io_submit_init_bio fs/ext4/page-io.c:428 [inline]
 io_submit_add_bh fs/ext4/page-io.c:464 [inline]
 ext4_bio_write_folio+0x731/0xa20 fs/ext4/page-io.c:609
 mpage_submit_folio fs/ext4/inode.c:2103 [inline]
 mpage_process_page_bufs+0x4a1/0x620 fs/ext4/inode.c:2214
 mpage_prepare_extent_to_map+0x7d4/0xc50 fs/ext4/inode.c:2753
 ext4_do_writepages+0x6fe/0x2770 fs/ext4/inode.c:2894
 ext4_writepages+0x18f/0x320 fs/ext4/inode.c:3042
 do_writepages+0x1c6/0x310 mm/page-writeback.c:2571
 __writeback_single_inode+0x7f/0x650 fs/fs-writeback.c:1764
 writeback_sb_inodes+0x4dd/0xaa0 fs/fs-writeback.c:2056
 __writeback_inodes_wb+0x94/0x1a0 fs/fs-writeback.c:2132
 wb_writeback+0x261/0x560 fs/fs-writeback.c:2243
 wb_check_start_all fs/fs-writeback.c:2369 [inline]
 wb_do_writeback fs/fs-writeback.c:2395 [inline]
 wb_workfn+0x4d1/0x930 fs/fs-writeback.c:2428
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0x4f0/0x9c0 kernel/workqueue.c:3385
 worker_thread+0x58a/0x780 kernel/workqueue.c:3466
 kthread+0x22a/0x280 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffffff86c07a00 of 8 bytes by task 6307 on cpu 0:
 mem_cgroup_flush_stats_ratelimited+0x29/0x50 mm/memcontrol.c:743
 count_shadow_nodes+0x6a/0x250 mm/workingset.c:692
 do_shrink_slab+0x63/0x660 mm/shrinker.c:382
 shrink_slab_memcg mm/shrinker.c:553 [inline]
 shrink_slab+0x545/0x8f0 mm/shrinker.c:631
 shrink_node_memcgs mm/vmscan.c:6173 [inline]
 shrink_node+0x6d4/0x20a0 mm/vmscan.c:6215
 shrink_zones mm/vmscan.c:6454 [inline]
 do_try_to_free_pages+0x408/0xc90 mm/vmscan.c:6516
 try_to_free_mem_cgroup_pages+0x201/0x420 mm/vmscan.c:6838
 try_charge_memcg+0x373/0xa10 mm/memcontrol.c:2627
 obj_cgroup_charge_pages mm/memcontrol.c:3069 [inline]
 __memcg_kmem_charge_page+0x1ce/0x3d0 mm/memcontrol.c:3113
 __alloc_frozen_pages_noprof+0x18a/0x350 mm/page_alloc.c:5243
 __alloc_pages_noprof mm/page_alloc.c:5260 [inline]
 alloc_pages_bulk_noprof+0x4d1/0x560 mm/page_alloc.c:5180
 alloc_pages_bulk_mempolicy_noprof+0x35b/0xeb0 mm/mempolicy.c:2798
 vm_area_alloc_pages mm/vmalloc.c:3700 [inline]
 __vmalloc_area_node mm/vmalloc.c:3878 [inline]
 __vmalloc_node_range_noprof+0x891/0x11c0 mm/vmalloc.c:4064
 __kvmalloc_node_noprof+0x3d4/0x640 mm/slub.c:6860
 futex_hash_allocate+0x190/0x9a0 kernel/futex/core.c:1815
 futex_hash_prctl+0xd8/0xf0 kernel/futex/core.c:1961
 __do_sys_prctl kernel/sys.c:2885 [inline]
 __se_sys_prctl+0x4f4/0x1400 kernel/sys.c:2534
 __x64_sys_prctl+0x67/0x80 kernel/sys.c:2534
 x64_sys_call+0x2533/0x3020 arch/x86/include/generated/asm/syscalls_64.h:158
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000ffffd375 -> 0x00000000ffffd376

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 6307 Comm: syz.0.569 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================
syz.0.569 invoked oom-killer: gfp_mask=0x402dc2(GFP_KERNEL_ACCOUNT|__GFP_HIGHMEM|__GFP_ZERO|__GFP_NOWARN), order=0, oom_score_adj=1000
CPU: 0 UID: 0 PID: 6307 Comm: syz.0.569 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 __dump_stack+0x1d/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x95/0xd0 lib/dump_stack.c:120
 dump_stack+0x15/0x1b lib/dump_stack.c:129
 dump_header+0x80/0x240 mm/oom_kill.c:464
 oom_kill_process+0x295/0x350 mm/oom_kill.c:1031
 out_of_memory+0x97d/0xb80 mm/oom_kill.c:1169
 mem_cgroup_out_of_memory mm/memcontrol.c:1907 [inline]
 mem_cgroup_oom mm/memcontrol.c:1930 [inline]
 try_charge_memcg+0x62f/0xa10 mm/memcontrol.c:2669
 obj_cgroup_charge_pages mm/memcontrol.c:3069 [inline]
 __memcg_kmem_charge_page+0x1ce/0x3d0 mm/memcontrol.c:3113
 __alloc_frozen_pages_noprof+0x18a/0x350 mm/page_alloc.c:5243
 alloc_pages_mpol+0xb3/0x260 mm/mempolicy.c:2490
 alloc_frozen_pages_noprof mm/mempolicy.c:2561 [inline]
 alloc_pages_noprof+0x8f/0x140 mm/mempolicy.c:2581
 vm_area_alloc_pages mm/vmalloc.c:3728 [inline]
 __vmalloc_area_node mm/vmalloc.c:3878 [inline]
 __vmalloc_node_range_noprof+0xaed/0x11c0 mm/vmalloc.c:4064
 __kvmalloc_node_noprof+0x3d4/0x640 mm/slub.c:6860
 futex_hash_allocate+0x190/0x9a0 kernel/futex/core.c:1815
 futex_hash_prctl+0xd8/0xf0 kernel/futex/core.c:1961
 __do_sys_prctl kernel/sys.c:2885 [inline]
 __se_sys_prctl+0x4f4/0x1400 kernel/sys.c:2534
 __x64_sys_prctl+0x67/0x80 kernel/sys.c:2534
 x64_sys_call+0x2533/0x3020 arch/x86/include/generated/asm/syscalls_64.h:158
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd5ef67cdd9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd5ee0d7028 EFLAGS: 00000246 ORIG_RAX: 000000000000009d
RAX: ffffffffffffffda RBX: 00007fd5ef8f5fa0 RCX: 00007fd5ef67cdd9
RDX: 0000000001000000 RSI: 0000000000000001 RDI: 000000000000004e
RBP: 00007fd5ef712d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd5ef8f6038 R14: 00007fd5ef8f5fa0 R15: 00007ffe7ab900f8
 </TASK>
memory: usage 307200kB, limit 307200kB, failcnt 3494
memory+swap: usage 310680kB, limit 9007199254740988kB, failcnt 0
kmem: usage 294864kB, limit 9007199254740988kB, failcnt 0
Memory cgroup stats for /syz0:
cache 8192
rss 8388608
shmem 0
mapped_file 0
dirty 0
writeback 0
workingset_refault_anon 6372
workingset_refault_file 2781
swap 4112384
swapcached 47292416
pgpgin 210520
pgpgout 208470
pgfault 206972
pgmajfault 1704
inactive_anon 0
active_anon 0
inactive_file 0
active_file 8192
unevictable 8388608
hierarchical_memory_limit 314572800
hierarchical_memsw_limit 9223372036854771712
total_cache 8192
total_rss 8388608
total_shmem 0
total_mapped_file 0
total_dirty 0
total_writeback 0
total_workingset_refault_anon 6372
total_workingset_refault_file 2781
total_swap 4112384
total_swapcached 47292416
total_pgpgin 210520
total_pgpgout 208470
total_pgfault 206972
total_pgmajfault 1704
total_inactive_anon 0
total_active_anon 0
total_inactive_file 0
total_active_file 8192
total_unevictable 8388608
oom-kill:constraint=CONSTRAINT_MEMCG,nodemask=(null),cpuset=syz0,mems_allowed=0,oom_memcg=/syz0,task_memcg=/syz0,task=syz.0.569,pid=6306,uid=0
Memory cgroup out of memory: Killed process 6306 (syz.0.569) total-vm:98536kB, anon-rss:9420kB, file-rss:26572kB, shmem-rss:0kB, UID:0 pgtables:152kB oom_score_adj:1000