linux-kernel - Re: [syzbot] [mm?] KCSAN: data-race in generic_fillattr / shmem

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Message-ID: <66ed89f7.050a0220.2abe4d.0017.GAE@google.com>
Date: Fri, 20 Sep 2024 07:43:03 -0700
From: syzbot <syzbot+702361cf7e3d95758761@...kaller.appspotmail.com>
To: aha310510@...il.com, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [mm?] KCSAN: data-race in generic_fillattr / shmem_mknod (2)

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KCSAN: data-race in ext4_fill_raw_inode / ext4_orphan_del

==================================================================
BUG: KCSAN: data-race in ext4_fill_raw_inode / ext4_orphan_del

write to 0xffff8881080b3214 of 4 bytes by task 3410 on cpu 1:
 ext4_orphan_del+0x550/0x6e0 fs/ext4/orphan.c:296
 ext4_evict_inode+0xac3/0xdc0 fs/ext4/inode.c:289
 evict+0x2f0/0x570 fs/inode.c:731
 iput_final fs/inode.c:1883 [inline]
 iput+0x42a/0x5b0 fs/inode.c:1909
 d_delete_notify include/linux/fsnotify.h:332 [inline]
 vfs_rmdir+0x29f/0x320 fs/namei.c:4353
 do_rmdir+0x194/0x320 fs/namei.c:4399
 __do_sys_unlinkat fs/namei.c:4575 [inline]
 __se_sys_unlinkat fs/namei.c:4569 [inline]
 __x64_sys_unlinkat+0xa2/0xb0 fs/namei.c:4569
 x64_sys_call+0x25fd/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:264
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x54/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

read to 0xffff8881080b3214 of 4 bytes by task 3404 on cpu 0:
 ext4_fill_raw_inode+0x28d/0xe80 fs/ext4/inode.c:4323
 ext4_do_update_inode fs/ext4/inode.c:5148 [inline]
 ext4_mark_iloc_dirty+0x2e9/0xe00 fs/ext4/inode.c:5778
 __ext4_mark_inode_dirty+0x314/0x440 fs/ext4/inode.c:5982
 __ext4_ext_dirty fs/ext4/extents.c:202 [inline]
 ext4_ext_rm_leaf fs/ext4/extents.c:2722 [inline]
 ext4_ext_remove_space+0x126d/0x2c80 fs/ext4/extents.c:2934
 ext4_ext_truncate+0xc4/0x150 fs/ext4/extents.c:4441
 ext4_truncate+0x776/0xb10 fs/ext4/inode.c:4215
 ext4_evict_inode+0x8b4/0xdc0 fs/ext4/inode.c:258
 evict+0x2f0/0x570 fs/inode.c:731
 iput_final fs/inode.c:1883 [inline]
 iput+0x42a/0x5b0 fs/inode.c:1909
 d_delete_notify include/linux/fsnotify.h:332 [inline]
 vfs_rmdir+0x29f/0x320 fs/namei.c:4353
 do_rmdir+0x194/0x320 fs/namei.c:4399
 __do_sys_unlinkat fs/namei.c:4575 [inline]
 __se_sys_unlinkat fs/namei.c:4569 [inline]
 __x64_sys_unlinkat+0xa2/0xb0 fs/namei.c:4569
 x64_sys_call+0x25fd/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:264
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x54/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

value changed: 0x0000079c -> 0x0000078b

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3404 Comm: syz-executor.0 Not tainted 6.11.0-syzkaller-07341-gbaeb9a7d8b60-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
==================================================================


Tested on:

commit:         baeb9a7d Merge tag 'sched-rt-2024-09-17' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1642ae9f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4ca35e71cb9a0a41
dashboard link: https://syzkaller.appspot.com/bug?extid=702361cf7e3d95758761
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=143cae9f980000