syzbot


KCSAN: data-race in mas_state_walk / mas_wr_store_entry

Status: moderation: reported on 2025/04/27 04:37
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+ff9c72a9eb3dc1c87021@syzkaller.appspotmail.com
First crash: 309d, last: 1d10h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
85f4fcf0-48cd-4362-824b-1b3d9de00613 assessment-kcsan Benign: ✅  Confident: ✅  KCSAN: data-race in mas_state_walk / mas_wr_store_entry 2026/02/25 00:32 2026/02/25 00:32 2026/02/25 00:43 305c0ec5cd886e2d13738e28e1b2df9b0ec20fc9
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

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

write to 0xffff888104fd7000 of 8 bytes by task 14733 on cpu 0:
 mte_set_node_dead lib/maple_tree.c:334 [inline]
 mas_put_in_tree lib/maple_tree.c:1565 [inline]
 mas_replace_node lib/maple_tree.c:1580 [inline]
 mas_wr_node_store lib/maple_tree.c:3553 [inline]
 mas_wr_store_entry+0x20c5/0x2ed0 lib/maple_tree.c:3764
 mas_store_prealloc+0x72e/0xa70 lib/maple_tree.c:5169
 vma_iter_store_overwrite mm/vma.h:607 [inline]
 vma_iter_store_new mm/vma.h:614 [inline]
 vma_complete+0x3c7/0x850 mm/vma.c:356
 __split_vma+0x593/0x640 mm/vma.c:566
 split_vma mm/vma.c:596 [inline]
 vma_modify+0xb2e/0xd00 mm/vma.c:1672
 vma_modify_flags+0x182/0x210 mm/vma.c:1700
 mprotect_fixup+0x312/0x5d0 mm/mprotect.c:756
 do_mprotect_pkey+0x67b/0x920 mm/mprotect.c:930
 __do_sys_mprotect mm/mprotect.c:951 [inline]
 __se_sys_mprotect mm/mprotect.c:948 [inline]
 __x64_sys_mprotect+0x48/0x60 mm/mprotect.c:948
 x64_sys_call+0x2768/0x3020 arch/x86/include/generated/asm/syscalls_64.h:11
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888104fd7000 of 8 bytes by task 14742 on cpu 1:
 ma_dead_node lib/maple_tree.c:572 [inline]
 mtree_range_walk lib/maple_tree.c:2580 [inline]
 mas_state_walk+0x485/0x650 lib/maple_tree.c:3298
 mas_walk+0x60/0x150 lib/maple_tree.c:4599
 lock_vma_under_rcu+0xc9/0x210 mm/mmap_lock.c:304
 do_user_addr_fault+0x232/0x1050 arch/x86/mm/fault.c:1325
 handle_page_fault arch/x86/mm/fault.c:1474 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1527
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

value changed: 0xffff88811478010e -> 0xffff888104fd7000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 14742 Comm: syz.9.1753 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
==================================================================

Crashes (118):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/28 23:06 upstream 2f9339c052bd 43249bac .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2026/02/27 07:48 upstream 3f4a08e64442 a2f13f71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2026/02/25 04:26 upstream 7dff99b35460 787dfb7c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2026/02/15 05:00 upstream 3e48a11675c5 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2026/02/12 10:43 upstream c22e26bd0906 76a109e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2026/02/09 00:35 upstream e98f34af6116 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2026/02/07 05:51 upstream 2687c848e578 f20fc9f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2026/02/01 22:29 upstream 9f2693489ef8 6b8752f2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2026/01/26 03:38 upstream 023777797472 55756628 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2026/01/24 01:24 upstream 5bde837031a3 4f25b9b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2026/01/21 22:50 upstream cf38b2340c0e 8fc37797 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2026/01/18 04:05 upstream d12453c7e281 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2026/01/15 04:57 upstream e0d4140e8043 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2026/01/05 03:08 upstream 54e82e93ca93 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2026/01/03 10:40 upstream 805f9a061372 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/12/29 18:26 upstream 7839932417dd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/12/29 04:02 upstream c875a6c32467 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/12/27 03:47 upstream 3f0e9c8cefa9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/12/16 12:33 upstream 40fbbd64bba6 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/12/13 02:04 upstream 187d0801404f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/12/09 02:52 upstream c2f2b01b74be d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/12/06 12:43 upstream 416f99c3b16f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/12/05 23:18 upstream d1d36025a617 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/12/03 05:12 upstream d61f1cc5db79 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/12/02 08:57 upstream 1d18101a644e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/12/01 13:09 upstream 7d0a66e4bb90 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/11/30 22:25 upstream e69c7c175115 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/11/30 02:42 upstream 6bda50f4333f d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/11/28 16:44 upstream e538109ac71d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/11/27 19:26 upstream 765e56e41a5a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/11/24 15:08 upstream ac3fd01e4c1e bf6fe8fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/11/24 03:33 upstream d0e88704d96c 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/11/22 04:47 upstream 2eba5e05d9bc 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/11/20 04:10 upstream 23cb64fb7625 26ee5237 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/11/18 23:02 upstream 5bebe8de1926 ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/11/13 13:51 upstream e927c520e1ba 07e030de .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/11/11 13:35 upstream 4427259cc7f7 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/11/08 15:31 upstream e811c33b1f13 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/11/05 12:29 upstream 17d85f33a83b a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/11/01 21:16 upstream 691d401c7e0e 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/10/31 08:04 upstream d127176862a9 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/10/29 17:09 upstream e53642b87a4f fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/10/24 16:38 upstream 6fab32bb6508 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/10/24 01:01 upstream 266ee584e55e c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/10/22 20:39 upstream dd72c8fcf6d3 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/10/19 20:51 upstream d9043c79ba68 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/10/19 08:11 upstream 1c64efcb083c 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/10/17 09:06 upstream 98ac9cc4b445 19568248 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/10/16 08:32 upstream 7ea30958b305 19568248 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/10/11 20:20 upstream 0739473694c4 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
2025/04/27 04:36 upstream 5bc1018675ec c6b4fb39 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_state_walk / mas_wr_store_entry
* Struck through repros no longer work on HEAD.