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ID Workflow Result Correct Bug Created Started Finished Revision Error
eba4707a-f867-4e57-9fd5-90454badbedf assessment-kcsan 🏃 KCSAN: data-race in mas_state_walk / mas_wr_store_entry 2026/01/10 08:55 2026/01/10 08:55 7519916073b761ced56a7b15fdeeb4674e8dc125

Crash report:
==================================================================
BUG: KCSAN: data-race in mas_state_walk / mas_wr_store_entry

write to 0xffff88810465aa08 of 8 bytes by task 15203 on cpu 1:
 mas_wr_slot_store lib/maple_tree.c:3585 [inline]
 mas_wr_store_entry+0x11e9/0x2750 lib/maple_tree.c:3761
 mas_store_prealloc+0x760/0xa90 lib/maple_tree.c:5169
 vma_iter_store_overwrite mm/vma.h:541 [inline]
 commit_merge+0x6a5/0x730 mm/vma.c:758
 vma_expand+0x1fe/0x460 mm/vma.c:1160
 vma_merge_new_range+0x296/0x310 mm/vma.c:1092
 __mmap_region mm/vma.c:2703 [inline]
 mmap_region+0xa71/0x1410 mm/vma.c:2786
 do_mmap+0x9b3/0xbe0 mm/mmap.c:558
 vm_mmap_pgoff+0x17a/0x2e0 mm/util.c:581
 ksys_mmap_pgoff+0xc2/0x310 mm/mmap.c:604
 x64_sys_call+0x16bb/0x3000 arch/x86/include/generated/asm/syscalls_64.h:10
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810465aa08 of 8 bytes by task 15205 on cpu 0:
 mtree_range_walk lib/maple_tree.c:2561 [inline]
 mas_state_walk+0x28f/0x650 lib/maple_tree.c:3298
 mas_walk+0x60/0x150 lib/maple_tree.c:4599
 lock_vma_under_rcu+0x95/0x1b0 mm/mmap_lock.c:253
 do_user_addr_fault+0x233/0x1080 arch/x86/mm/fault.c:1327
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

value changed: 0x00007fcd4e2b5fff -> 0x00007fcd4e294fff

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 15205 Comm: syz.0.3908 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================

Trajectory:
Seq Timestamp Type Name Duration
0/0 2026/01/10 08:55 flow assessment-kcsan
Model:
unknown

1/1 2026/01/10 08:55 action kernel-checkouter
0m Model:
unknown

Results:
map[KernelSrc:/usr/local/google/home/dvyukov/syzkaller/agent/workdir/cache/src/52d5b556e0818c1fa1e9e0ef8e0fa1ffbbead1f7]

2/1 2026/01/10 08:56 action kernel-builder
3m Model:
unknown

Results:
map[KernelObj:/usr/local/google/home/dvyukov/syzkaller/agent/workdir/cache/build/063b050f281ddd546cf041f44e4c92e4d851c023]

3/1 2026/01/10 09:00 action codesearch-prepare
Model:
unknown

LLM Calls Summary:
Total Calls Total Tokens Avg Tokens Total Duration (Seconds) Avg Duration (Seconds)
Tool Calls Summary:
Total Calls Total Duration (Seconds) Avg Duration (Seconds)