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KCSAN: data-race in mas_replace_node / mas_state_walk (2)

Status: moderation: reported on 2025/04/29 11:19
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+b737e61fbcac97053f96@syzkaller.appspotmail.com
First crash: 4d23h, last: 3d03h
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in mas_replace_node / mas_state_walk mm 155 480d 513d 0/28 auto-obsoleted due to no activity on 2024/02/06 14:39

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

write to 0xffff888106216600 of 8 bytes by task 15809 on cpu 0:
 mte_set_node_dead lib/maple_tree.c:337 [inline]
 mas_put_in_tree lib/maple_tree.c:1735 [inline]
 mas_replace_node+0x1c9/0x440 lib/maple_tree.c:1749
 mas_wr_node_store lib/maple_tree.c:3863 [inline]
 mas_wr_store_entry+0x2425/0x2b60 lib/maple_tree.c:4083
 mas_store_prealloc+0x74d/0x9e0 lib/maple_tree.c:5475
 vma_iter_store_overwrite mm/vma.h:448 [inline]
 vma_iter_store_new+0x1c5/0x200 mm/vma.h:455
 vma_complete+0x125/0x570 mm/vma.c:323
 __split_vma+0x54c/0x610 mm/vma.c:523
 split_vma mm/vma.c:553 [inline]
 vma_modify+0x107/0x210 mm/vma.c:1579
 vma_modify_flags+0x101/0x130 mm/vma.c:1605
 mprotect_fixup+0x2cc/0x570 mm/mprotect.c:658
 do_mprotect_pkey+0x6d6/0x980 mm/mprotect.c:832
 __do_sys_mprotect mm/mprotect.c:853 [inline]
 __se_sys_mprotect mm/mprotect.c:850 [inline]
 __x64_sys_mprotect+0x48/0x60 mm/mprotect.c:850
 x64_sys_call+0x2794/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:11
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888106216600 of 8 bytes by task 15814 on cpu 1:
 ma_dead_node lib/maple_tree.c:575 [inline]
 mtree_range_walk lib/maple_tree.c:2788 [inline]
 mas_state_walk+0x485/0x650 lib/maple_tree.c:3605
 mas_walk+0x30/0x120 lib/maple_tree.c:4905
 lock_vma_under_rcu+0xa2/0x2f0 mm/memory.c:6553
 do_user_addr_fault+0x233/0x1090 arch/x86/mm/fault.c:1328
 handle_page_fault arch/x86/mm/fault.c:1480 [inline]
 exc_page_fault+0x54/0xc0 arch/x86/mm/fault.c:1538
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

value changed: 0xffff88810463e306 -> 0xffff888106216600

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 15814 Comm: syz.2.3381 Not tainted 6.15.0-rc4-syzkaller-00051-g7a13c14ee59d #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/01 07:35 upstream 7a13c14ee59d ce7952f4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_replace_node / mas_state_walk
2025/04/29 11:19 upstream ca91b9500108 aeb6ec69 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mas_replace_node / mas_state_walk
* Struck through repros no longer work on HEAD.