From: Guenter Roeck <linux@roeck-us.net>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Rich Felker <dalias@libc.org>,
John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Miklos Szeredi <mszeredi@redhat.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-api@vger.kernel.org, linux-man@vger.kernel.org,
linux-security-module@vger.kernel.org,
Karel Zak <kzak@redhat.com>, Ian Kent <raven@themaw.net>,
David Howells <dhowells@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <christian@brauner.io>,
Amir Goldstein <amir73il@gmail.com>,
Matthew House <mattlloydhouse@gmail.com>,
Florian Weimer <fweimer@redhat.com>,
Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH v4 5/6] add listmount(2) syscall
Date: Thu, 11 Jan 2024 15:57:28 -0800 [thread overview]
Message-ID: <77b38aa7-a8b1-4450-8c50-379f130dda16@roeck-us.net> (raw)
In-Reply-To: <CAHk-=wjh6Cypo8WC-McXgSzCaou3UXccxB+7PVeSuGR8AjCphg@mail.gmail.com>
On 1/11/24 12:14, Linus Torvalds wrote:
> On Thu, 11 Jan 2024 at 10:57, Guenter Roeck <linux@roeck-us.net> wrote:
>>
>> Any variance of put_user() with &buf[ctr] or buf + ctr fails
>> if ctr is a variable and permitted to be != 0.
>
> Crazy. But the 64-bit put_user() is a bit special and tends to require
> more registers (the 64-bit value is passed in two registers), so that
> probably then results in the ICE.
>
> Side note: looking at the SH version of __put_user_u64(), I think it's
> buggy and is missing the exception handler for the second 32-bit move.
> I dunno, I don't read sh asm, but it looks suspicious.
>
I wonder if something may be wrong with the definition and use of __m
for u64 accesses. The code below also fixes the build problem.
But then I really don't know what
struct __large_struct { unsigned long buf[100]; };
#define __m(x) (*(struct __large_struct __user *)(x))
is supposed to be doing in the first place, and I still don't understand
why the problem only shows up with CONFIG_MMU=n.
Guenter
---
diff --git a/arch/sh/include/asm/uaccess_32.h b/arch/sh/include/asm/uaccess_32.h
index 5d7ddc092afd..f0451a37b6ff 100644
--- a/arch/sh/include/asm/uaccess_32.h
+++ b/arch/sh/include/asm/uaccess_32.h
@@ -196,7 +196,7 @@ __asm__ __volatile__( \
".long 1b, 3b\n\t" \
".previous" \
: "=r" (retval) \
- : "r" (val), "m" (__m(addr)), "i" (-EFAULT), "0" (retval) \
+ : "r" (val), "m" (*(u64 *)(addr)), "i" (-EFAULT), "0" (retval) \
: "memory"); })
#else
#define __put_user_u64(val,addr,retval) \
@@ -218,7 +218,7 @@ __asm__ __volatile__( \
".long 1b, 3b\n\t" \
".previous" \
: "=r" (retval) \
- : "r" (val), "m" (__m(addr)), "i" (-EFAULT), "0" (retval) \
+ : "r" (val), "m" (*(u64 *)(addr)), "i" (-EFAULT), "0" (retval) \
: "memory"); })
#endif
next prev parent reply other threads:[~2024-01-11 23:57 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-25 14:01 [PATCH v4 0/6] querying mount attributes Miklos Szeredi
2023-10-25 14:01 ` [PATCH v4 1/6] add unique mount ID Miklos Szeredi
2023-10-25 14:02 ` [PATCH v4 2/6] mounts: keep list of mounts in an rbtree Miklos Szeredi
2023-10-27 3:11 ` Ian Kent
2023-10-27 8:17 ` Miklos Szeredi
2023-10-28 1:36 ` Ian Kent
2023-10-30 5:37 ` Ian Kent
2023-10-30 5:45 ` Ian Kent
2023-10-30 9:06 ` Miklos Szeredi
2023-10-31 1:23 ` Ian Kent
2023-10-25 14:02 ` [PATCH v4 3/6] namespace: extract show_path() helper Miklos Szeredi
2023-10-25 14:02 ` [PATCH v4 4/6] add statmount(2) syscall Miklos Szeredi
2023-11-08 2:58 ` Paul Moore
2023-11-08 7:58 ` Christian Brauner
2023-11-08 20:10 ` Paul Moore
2023-11-10 17:00 ` Paul Moore
2023-11-12 13:05 ` Christian Brauner
2023-11-12 20:29 ` Paul Moore
2023-10-25 14:02 ` [PATCH v4 5/6] add listmount(2) syscall Miklos Szeredi
2023-11-07 21:23 ` Jonathan Corbet
2023-11-08 7:53 ` Christian Brauner
2023-11-08 16:20 ` Jonathan Corbet
2023-11-08 16:23 ` Christian Brauner
2023-11-08 2:58 ` Paul Moore
2024-01-10 22:23 ` Guenter Roeck
2024-01-11 0:32 ` Linus Torvalds
2024-01-11 5:12 ` Guenter Roeck
2024-01-11 18:57 ` Guenter Roeck
2024-01-11 20:14 ` Linus Torvalds
2024-01-11 23:01 ` Arnd Bergmann
2024-01-11 23:57 ` Guenter Roeck [this message]
2024-01-12 3:40 ` Linus Torvalds
2024-01-12 5:24 ` Guenter Roeck
2024-01-12 9:00 ` Christian Brauner
2024-01-23 14:14 ` John Paul Adrian Glaubitz
2024-01-23 15:31 ` Guenter Roeck
2024-01-23 14:14 ` John Paul Adrian Glaubitz
2023-10-25 14:02 ` [PATCH v4 6/6] wire up syscalls for statmount/listmount Miklos Szeredi
2024-01-09 1:11 ` Florian Fainelli
2023-11-01 11:13 ` [PATCH v4 0/6] querying mount attributes Christian Brauner
2023-11-01 13:18 ` Miklos Szeredi
2023-11-01 15:54 ` Christian Brauner
2023-11-01 11:52 ` Ian Kent
2023-11-06 12:10 ` Karel Zak
2023-11-06 13:33 ` Amir Goldstein
2023-11-07 0:47 ` Ian Kent
2023-11-06 23:54 ` Ian Kent
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