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: 53d, last: 3d09h

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

write to 0xffff88810328b010 of 8 bytes by task 7294 on cpu 1:
 mas_wr_slot_store lib/maple_tree.c:3919 [inline]
 mas_wr_store_entry+0x1581/0x2b50 lib/maple_tree.c:4095
 mas_store_prealloc+0x74d/0x9e0 lib/maple_tree.c:5506
 vma_iter_store_overwrite mm/vma.h:502 [inline]
 commit_merge+0x6a5/0x730 mm/vma.c:762
 vma_expand+0x1d0/0x370 mm/vma.c:1153
 vma_merge_new_range+0x296/0x310 mm/vma.c:1091
 __mmap_region mm/vma.c:2617 [inline]
 mmap_region+0x9fa/0x1580 mm/vma.c:2692
 do_mmap+0x9b3/0xbe0 mm/mmap.c:561
 vm_mmap_pgoff+0x17a/0x2e0 mm/util.c:579
 ksys_mmap_pgoff+0xc2/0x310 mm/mmap.c:607
 x64_sys_call+0x1602/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:10
 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 0xffff88810328b010 of 8 bytes by task 7296 on cpu 0:
 mtree_range_walk lib/maple_tree.c:2781 [inline]
 mas_state_walk+0x2f5/0x650 lib/maple_tree.c:3630
 mas_walk+0x30/0x120 lib/maple_tree.c:4936
 lock_vma_under_rcu+0xa2/0x2f0 mm/mmap_lock.c:143
 do_user_addr_fault+0x233/0x1090 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:623

value changed: 0x00007fde631e5fff -> 0x00007fde631c4fff

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 7296 Comm: syz.2.1494 Not tainted 6.16.0-rc1-syzkaller-00239-g08215f5486ec #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================

Crashes (25):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/16 04:54 upstream 08215f5486ec 5f4b362d .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
2025/06/15 00:44 upstream 4774cfe3543a 5f4b362d .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
2025/06/12 02:54 upstream 488ef3560196 98683f8f .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
2025/06/08 14:36 upstream 8630c59e9936 4826c28e .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
2025/06/07 19:49 upstream 5b032cac6225 4826c28e .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
2025/06/04 06:48 upstream 5abc7438f1e9 a30356b7 .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
2025/06/04 00:17 upstream 546b1c9e93c2 a30356b7 .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
2025/06/02 19:08 upstream cd2e103d57e5 b396b4bf .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
2025/06/01 07:07 upstream 4cb6c8af8591 3d2f584d .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
2025/05/27 01:39 upstream 0ff41df1cb26 874a1386 .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
2025/05/25 17:49 upstream d0c22de9995b ed351ea7 .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
2025/05/24 23:30 upstream b1427432d3b6 ed351ea7 .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
2025/05/24 10:25 upstream 4856ebd99715 ed351ea7 .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
2025/05/23 12:49 upstream 94305e83eccb fa44301a .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
2025/05/19 09:25 upstream a5806cd506af f41472b0 .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
2025/05/18 14:13 upstream 5723cc3450bc f41472b0 .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
2025/05/16 18:22 upstream fee3e843b309 cfde8269 .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
2025/05/15 20:22 upstream 088d13246a46 cfde8269 .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
2025/05/12 04:53 upstream cd802e7e5f1e 77908e5f .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
2025/05/11 02:33 upstream bec6f00f120e 77908e5f .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
2025/05/10 13:58 upstream 0e1329d4045c 77908e5f .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
2025/05/07 02:02 upstream 0d8d44db295c 350f4ffc .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
2025/05/03 00:27 upstream 2bfcee565c3a b0714e37 .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
2025/04/29 02:53 upstream f15d97df5afa aeb6ec69 .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.