* [syzbot] [fuse?] KMSAN: uninit-value in fuse_fileattr_get
@ 2026-02-06 3:37 syzbot
2026-02-06 3:46 ` Qing Wang
` (3 more replies)
0 siblings, 4 replies; 8+ messages in thread
From: syzbot @ 2026-02-06 3:37 UTC (permalink / raw)
To: linux-fsdevel, linux-kernel, miklos, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 18f7fcd5e69a Linux 6.19-rc8
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16bafc5a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=9682a42d8ec8b05c
dashboard link: https://syzkaller.appspot.com/bug?extid=7c31755f2cea07838b0c
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1329b322580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=178a425a580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c8e19a1c3a97/disk-18f7fcd5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ffdc9733836e/vmlinux-18f7fcd5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8cdf30f0d2d2/bzImage-18f7fcd5.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7c31755f2cea07838b0c@syzkaller.appspotmail.com
=====================================================
BUG: KMSAN: uninit-value in fuse_fileattr_get+0xeb4/0x1450 fs/fuse/ioctl.c:517
fuse_fileattr_get+0xeb4/0x1450 fs/fuse/ioctl.c:517
vfs_fileattr_get fs/file_attr.c:94 [inline]
__do_sys_file_getattr fs/file_attr.c:416 [inline]
__se_sys_file_getattr+0x6cb/0xbd0 fs/file_attr.c:372
__x64_sys_file_getattr+0xe4/0x150 fs/file_attr.c:372
x64_sys_call+0x17cd/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:469
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Local variable fa.i created at:
__do_sys_file_getattr fs/file_attr.c:380 [inline]
__se_sys_file_getattr+0x8c/0xbd0 fs/file_attr.c:372
__x64_sys_file_getattr+0xe4/0x150 fs/file_attr.c:372
CPU: 1 UID: 0 PID: 6065 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
=====================================================
---
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^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [syzbot] [fuse?] KMSAN: uninit-value in fuse_fileattr_get 2026-02-06 3:37 [syzbot] [fuse?] KMSAN: uninit-value in fuse_fileattr_get syzbot @ 2026-02-06 3:46 ` Qing Wang 2026-02-06 4:16 ` syzbot 2026-02-06 5:50 ` Edward Adam Davis ` (2 subsequent siblings) 3 siblings, 1 reply; 8+ messages in thread From: Qing Wang @ 2026-02-06 3:46 UTC (permalink / raw) To: syzbot+7c31755f2cea07838b0c Cc: linux-fsdevel, linux-kernel, miklos, syzkaller-bugs #syz test diff --git a/fs/file_attr.c b/fs/file_attr.c index 13cdb31a3e94..4f514e487e35 100644 --- a/fs/file_attr.c +++ b/fs/file_attr.c @@ -413,6 +413,7 @@ SYSCALL_DEFINE5(file_getattr, int, dfd, const char __user *, filename, return error; } + memset(&fa, 0, sizeof(struct file_kattr)); error = vfs_fileattr_get(filepath.dentry, &fa); if (error == -ENOIOCTLCMD || error == -ENOTTY) error = -EOPNOTSUPP; ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [syzbot] [fuse?] KMSAN: uninit-value in fuse_fileattr_get 2026-02-06 3:46 ` Qing Wang @ 2026-02-06 4:16 ` syzbot 0 siblings, 0 replies; 8+ messages in thread From: syzbot @ 2026-02-06 4:16 UTC (permalink / raw) To: linux-fsdevel, linux-kernel, miklos, syzkaller-bugs, wangqing7171 Hello, syzbot has tested the proposed patch and the reproducer did not trigger any issue: Reported-by: syzbot+7c31755f2cea07838b0c@syzkaller.appspotmail.com Tested-by: syzbot+7c31755f2cea07838b0c@syzkaller.appspotmail.com Tested on: commit: 06bc4e26 Merge tag 'block-6.19-20260205' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1498e402580000 kernel config: https://syzkaller.appspot.com/x/.config?x=9682a42d8ec8b05c dashboard link: https://syzkaller.appspot.com/bug?extid=7c31755f2cea07838b0c compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 patch: https://syzkaller.appspot.com/x/patch.diff?x=17f0e402580000 Note: testing is done by a robot and is best-effort only. ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [syzbot] [fuse?] KMSAN: uninit-value in fuse_fileattr_get 2026-02-06 3:37 [syzbot] [fuse?] KMSAN: uninit-value in fuse_fileattr_get syzbot 2026-02-06 3:46 ` Qing Wang @ 2026-02-06 5:50 ` Edward Adam Davis 2026-02-06 6:20 ` syzbot 2026-02-06 6:00 ` Qing Wang 2026-02-06 6:20 ` [PATCH] fs: init flags_valid before calling vfs_fileattr_get Edward Adam Davis 3 siblings, 1 reply; 8+ messages in thread From: Edward Adam Davis @ 2026-02-06 5:50 UTC (permalink / raw) To: syzbot+7c31755f2cea07838b0c; +Cc: linux-kernel, syzkaller-bugs #syz test diff --git a/fs/file_attr.c b/fs/file_attr.c index 13cdb31a3e94..4889cf59b256 100644 --- a/fs/file_attr.c +++ b/fs/file_attr.c @@ -377,7 +377,7 @@ SYSCALL_DEFINE5(file_getattr, int, dfd, const char __user *, filename, struct filename *name __free(putname) = NULL; unsigned int lookup_flags = 0; struct file_attr fattr; - struct file_kattr fa; + struct file_kattr fa = { .flags_valid = true }; /* hint only */ int error; BUILD_BUG_ON(sizeof(struct file_attr) < FILE_ATTR_SIZE_VER0); ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [syzbot] [fuse?] KMSAN: uninit-value in fuse_fileattr_get 2026-02-06 5:50 ` Edward Adam Davis @ 2026-02-06 6:20 ` syzbot 0 siblings, 0 replies; 8+ messages in thread From: syzbot @ 2026-02-06 6:20 UTC (permalink / raw) To: eadavis, linux-kernel, syzkaller-bugs Hello, syzbot has tested the proposed patch and the reproducer did not trigger any issue: Reported-by: syzbot+7c31755f2cea07838b0c@syzkaller.appspotmail.com Tested-by: syzbot+7c31755f2cea07838b0c@syzkaller.appspotmail.com Tested on: commit: b7ff7151 Merge tag 'hwmon-for-v6.19-final' of git://gi.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=145e878a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=9682a42d8ec8b05c dashboard link: https://syzkaller.appspot.com/bug?extid=7c31755f2cea07838b0c compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 patch: https://syzkaller.appspot.com/x/patch.diff?x=10bc27fa580000 Note: testing is done by a robot and is best-effort only. ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [syzbot] [fuse?] KMSAN: uninit-value in fuse_fileattr_get 2026-02-06 3:37 [syzbot] [fuse?] KMSAN: uninit-value in fuse_fileattr_get syzbot 2026-02-06 3:46 ` Qing Wang 2026-02-06 5:50 ` Edward Adam Davis @ 2026-02-06 6:00 ` Qing Wang 2026-02-06 6:53 ` syzbot 2026-02-06 6:20 ` [PATCH] fs: init flags_valid before calling vfs_fileattr_get Edward Adam Davis 3 siblings, 1 reply; 8+ messages in thread From: Qing Wang @ 2026-02-06 6:00 UTC (permalink / raw) To: syzbot+7c31755f2cea07838b0c Cc: linux-fsdevel, linux-kernel, miklos, syzkaller-bugs #syz test diff --git a/fs/file_attr.c b/fs/file_attr.c index 13cdb31a3e94..8b5565cbccb0 100644 --- a/fs/file_attr.c +++ b/fs/file_attr.c @@ -377,7 +377,7 @@ SYSCALL_DEFINE5(file_getattr, int, dfd, const char __user *, filename, struct filename *name __free(putname) = NULL; unsigned int lookup_flags = 0; struct file_attr fattr; - struct file_kattr fa; + struct file_kattr fa = {}; int error; BUILD_BUG_ON(sizeof(struct file_attr) < FILE_ATTR_SIZE_VER0); ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [syzbot] [fuse?] KMSAN: uninit-value in fuse_fileattr_get 2026-02-06 6:00 ` Qing Wang @ 2026-02-06 6:53 ` syzbot 0 siblings, 0 replies; 8+ messages in thread From: syzbot @ 2026-02-06 6:53 UTC (permalink / raw) To: linux-fsdevel, linux-kernel, miklos, syzkaller-bugs, wangqing7171 Hello, syzbot has tested the proposed patch and the reproducer did not trigger any issue: Reported-by: syzbot+7c31755f2cea07838b0c@syzkaller.appspotmail.com Tested-by: syzbot+7c31755f2cea07838b0c@syzkaller.appspotmail.com Tested on: commit: b7ff7151 Merge tag 'hwmon-for-v6.19-final' of git://gi.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16fe878a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=9682a42d8ec8b05c dashboard link: https://syzkaller.appspot.com/bug?extid=7c31755f2cea07838b0c compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 patch: https://syzkaller.appspot.com/x/patch.diff?x=14978a52580000 Note: testing is done by a robot and is best-effort only. ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH] fs: init flags_valid before calling vfs_fileattr_get 2026-02-06 3:37 [syzbot] [fuse?] KMSAN: uninit-value in fuse_fileattr_get syzbot ` (2 preceding siblings ...) 2026-02-06 6:00 ` Qing Wang @ 2026-02-06 6:20 ` Edward Adam Davis 3 siblings, 0 replies; 8+ messages in thread From: Edward Adam Davis @ 2026-02-06 6:20 UTC (permalink / raw) To: syzbot+7c31755f2cea07838b0c Cc: linux-fsdevel, linux-kernel, miklos, brauner, aalbersh, syzkaller-bugs syzbot reported a uninit-value bug in [1]. Similar to the "*get" context where the kernel's internal file_kattr structure is initialized before calling vfs_fileattr_get(), we should use the same mechanism when using fa. [1] BUG: KMSAN: uninit-value in fuse_fileattr_get+0xeb4/0x1450 fs/fuse/ioctl.c:517 fuse_fileattr_get+0xeb4/0x1450 fs/fuse/ioctl.c:517 vfs_fileattr_get fs/file_attr.c:94 [inline] __do_sys_file_getattr fs/file_attr.c:416 [inline] Local variable fa.i created at: __do_sys_file_getattr fs/file_attr.c:380 [inline] __se_sys_file_getattr+0x8c/0xbd0 fs/file_attr.c:372 Reported-by: syzbot+7c31755f2cea07838b0c@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=7c31755f2cea07838b0c Tested-by: syzbot+7c31755f2cea07838b0c@syzkaller.appspotmail.com Signed-off-by: Edward Adam Davis <eadavis@qq.com> --- fs/file_attr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/file_attr.c b/fs/file_attr.c index 13cdb31a3e94..4889cf59b256 100644 --- a/fs/file_attr.c +++ b/fs/file_attr.c @@ -377,7 +377,7 @@ SYSCALL_DEFINE5(file_getattr, int, dfd, const char __user *, filename, struct filename *name __free(putname) = NULL; unsigned int lookup_flags = 0; struct file_attr fattr; - struct file_kattr fa; + struct file_kattr fa = { .flags_valid = true }; /* hint only */ int error; BUILD_BUG_ON(sizeof(struct file_attr) < FILE_ATTR_SIZE_VER0); -- 2.43.0 ^ permalink raw reply related [flat|nested] 8+ messages in thread
end of thread, other threads:[~2026-02-06 6:53 UTC | newest] Thread overview: 8+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2026-02-06 3:37 [syzbot] [fuse?] KMSAN: uninit-value in fuse_fileattr_get syzbot 2026-02-06 3:46 ` Qing Wang 2026-02-06 4:16 ` syzbot 2026-02-06 5:50 ` Edward Adam Davis 2026-02-06 6:20 ` syzbot 2026-02-06 6:00 ` Qing Wang 2026-02-06 6:53 ` syzbot 2026-02-06 6:20 ` [PATCH] fs: init flags_valid before calling vfs_fileattr_get Edward Adam Davis
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