linux-kernel - [syzbot] [mm?] KCSAN: data-race in getrusage / try_to_unmap

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Message-ID: <67ee3330.050a0220.9040b.014e.GAE@google.com>
Date: Thu, 03 Apr 2025 00:05:20 -0700
From: syzbot <syzbot+988c9343ca9f2c49b9c4@...kaller.appspotmail.com>
To: akpm@...ux-foundation.org, linux-kernel@...r.kernel.org, 
	linux-mm@...ck.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [mm?] KCSAN: data-race in getrusage / try_to_unmap_one (2)

Hello,

syzbot found the following issue on:

HEAD commit:    92b71befc349 Merge tag 'objtool-urgent-2025-04-01' of git:..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=106d5274580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a8120cade23cf14e
dashboard link: https://syzkaller.appspot.com/bug?extid=988c9343ca9f2c49b9c4
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2e7df7bc2f52/disk-92b71bef.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/be59123d5efb/vmlinux-92b71bef.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7c9eff86053e/bzImage-92b71bef.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+988c9343ca9f2c49b9c4@...kaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in getrusage / try_to_unmap_one

write to 0xffff888104235900 of 8 bytes by task 3866 on cpu 0:
 update_hiwater_rss include/linux/mm.h:2754 [inline]
 try_to_unmap_one+0xebb/0x1f60 mm/rmap.c:2061
 __rmap_walk_file+0x1c1/0x2c0 mm/rmap.c:2897
 try_to_unmap+0x1b7/0x1e0 mm/rmap.c:-1
 shrink_folio_list+0x11f6/0x2670 mm/vmscan.c:1373
 reclaim_folio_list+0x83/0x2f0 mm/vmscan.c:2217
 reclaim_pages+0x218/0x280 mm/vmscan.c:2254
 madvise_cold_or_pageout_pte_range+0xd4f/0xdb0 mm/madvise.c:558
 walk_pmd_range mm/pagewalk.c:130 [inline]
 walk_pud_range mm/pagewalk.c:226 [inline]
 walk_p4d_range mm/pagewalk.c:264 [inline]
 walk_pgd_range+0x7e5/0x1120 mm/pagewalk.c:305
 __walk_page_range+0xed/0x350 mm/pagewalk.c:412
 walk_page_range_mm+0x369/0x4c0 mm/pagewalk.c:505
 walk_page_range+0x56/0x70 mm/pagewalk.c:584
 madvise_pageout_page_range mm/madvise.c:617 [inline]
 madvise_pageout mm/madvise.c:644 [inline]
 madvise_vma_behavior mm/madvise.c:1269 [inline]
 madvise_walk_vmas mm/madvise.c:1530 [inline]
 madvise_do_behavior+0x1aeb/0x2530 mm/madvise.c:1695
 do_madvise mm/madvise.c:1782 [inline]
 __do_sys_madvise mm/madvise.c:1790 [inline]
 __se_sys_madvise mm/madvise.c:1788 [inline]
 __x64_sys_madvise+0xcb/0x100 mm/madvise.c:1788
 x64_sys_call+0x23b8/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:29
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888104235900 of 8 bytes by task 3858 on cpu 1:
 get_mm_hiwater_rss include/linux/mm.h:2741 [inline]
 setmax_mm_hiwater_rss include/linux/mm.h:2771 [inline]
 getrusage+0xa17/0xb70 kernel/sys.c:1876
 io_sq_thread+0x5e0/0x1140 io_uring/sqpoll.c:310
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x00000000000016f1 -> 0x0000000000001951

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3858 Comm: iou-sqp-3852 Not tainted 6.14.0-syzkaller-12508-g92b71befc349 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================


---
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