From nobody Tue Oct 7 20:54:59 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B827F19C54F; Sun, 6 Jul 2025 17:37:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751823458; cv=none; b=M+mcRpJQzxYIaIc1Q2KjK8zC5boUm1KRdAHTxaWLrTytrLjdwG1djXGYDeBHhpKD4k6AFyuCebYA2gp2nj4cY5/odg8OrioIh9dDDr3DOOscdIzCEGb/te5l4kfre6haVDAqQlh9R0CnKN5F1+jz0nX0CrVwljOcvj/hdfNaz34= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751823458; c=relaxed/simple; bh=Yezh1PpcDSnMIsQt/1ue+JNou0BqpTIh4TMeGHqSd4o=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=EnKanAp/yN51hxDN+a9wlxaDhtpnG5v15f+b4+N0Z6/oPd6PXxF9cqEtnIhJ7IKQugicuX1+25KgGUyBa2guBrliUKCLzqythfdPyC9tQk9F8aEF9B2WNWCotOqtukK+4R3SgaFvZeIvh+oDsYakVSVp5EEsSY/r1pyHR8WP7bc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lJgCPADR; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="lJgCPADR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D591BC4CEEE; Sun, 6 Jul 2025 17:37:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751823456; bh=Yezh1PpcDSnMIsQt/1ue+JNou0BqpTIh4TMeGHqSd4o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lJgCPADR2ekdfgwOWk/dsELsGQzgTRkDGth8uwcI8eKSU21X/oqBbIscR+qFLH96s 4yU6AhXki8Dkv+qdFY5rUeO4XqXvtCqqlKQoEKWnUm1FC7IqeLP0xQQ7AHDBuPLXvi R1ryKK55/ujdlp9C9mqF993dg7PFuyyQPhAVhIsGErECvqXMeb9+3M0NiRldjOezLh zB646vD1yem0Vo0WlT/eVudEaML7JKwZtstdg4KWBZVXUZlYGeWcRXFsFbv/j2YKU/ 3VZJ2zHBf9CyM0t1si6JbNFmduZesKiE58rabaI8+eJFVe+uySZI8dPlQcgCJ4D1So 4vLdGj4K0bzag== Date: Sun, 6 Jul 2025 19:37:33 +0200 From: Alejandro Colomar To: linux-mm@kvack.org, linux-hardening@vger.kernel.org Cc: Alejandro Colomar , Kees Cook , Christopher Bazley , shadow <~hallyn/shadow@lists.sr.ht>, linux-kernel@vger.kernel.org, Andrew Morton , kasan-dev@googlegroups.com, Dmitry Vyukov , Alexander Potapenko , Marco Elver , Christoph Lameter , David Rientjes , Vlastimil Babka , Roman Gushchin , Harry Yoo , Andrew Clayton Subject: [RFC v2 1/5] vsprintf: Add [v]seprintf(), [v]stprintf() Message-ID: <64334f0b94d6b853e6104ec4f89bcf910978db76.1751823326.git.alx@kernel.org> X-Mailer: git-send-email 2.50.0 References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" seprintf() =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D seprintf() is a function similar to stpcpy(3) in the sense that it returns a pointer that is suitable for chaining to other copy operations. It takes a pointer to the end of the buffer as a sentinel for when to truncate, which unlike a size, doesn't need to be updated after every call. This makes it much more ergonomic, avoiding manually calculating the size after each copy, which is error prone. It also makes error handling much easier, by reporting truncation with a null pointer, which is accepted and transparently passed down by subsequent seprintf() calls. This results in only needing to report errors once after a chain of seprintf() calls, unlike snprintf(3), which requires checking after every call. p =3D buf; e =3D buf + countof(buf); p =3D seprintf(p, e, foo); p =3D seprintf(p, e, bar); if (p =3D=3D NULL) goto trunc; vs len =3D 0; size =3D countof(buf); len +=3D snprintf(buf + len, size - len, foo); if (len >=3D size) goto trunc; len +=3D snprintf(buf + len, size - len, bar); if (len >=3D size) goto trunc; And also better than scnprintf() calls: len =3D 0; size =3D countof(buf); len +=3D scnprintf(buf + len, size - len, foo); len +=3D scnprintf(buf + len, size - len, bar); if (len >=3D size) goto trunc; It seems aparent that it's a more elegant approach to string catenation. stprintf() =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D stprintf() is a helper that is needed for implementing seprintf() --although it could be open-coded within vseprintf(), of course--, but it's also useful by itself. It has the same interface properties as strscpy(): that is, it copies with truncation, and reports truncation with -E2BIG. It would be useful to replace some calls to snprintf(3) and scnprintf() which don't need chaining, and where it's simpler to pass a size. It is better than plain snprintf(3), because it results in simpler error detection (it doesn't need a check >=3Dcountof(buf), but rather <0). Cc: Kees Cook Cc: Christopher Bazley Signed-off-by: Alejandro Colomar --- include/linux/sprintf.h | 4 ++ lib/vsprintf.c | 109 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 113 insertions(+) diff --git a/include/linux/sprintf.h b/include/linux/sprintf.h index 51cab2def9ec..c3dbfd2efd2b 100644 --- a/include/linux/sprintf.h +++ b/include/linux/sprintf.h @@ -11,8 +11,12 @@ __printf(2, 3) int sprintf(char *buf, const char * fmt, = ...); __printf(2, 0) int vsprintf(char *buf, const char *, va_list); __printf(3, 4) int snprintf(char *buf, size_t size, const char *fmt, ...); __printf(3, 0) int vsnprintf(char *buf, size_t size, const char *fmt, va_l= ist args); +__printf(3, 4) int stprintf(char *buf, size_t size, const char *fmt, ...); +__printf(3, 0) int vstprintf(char *buf, size_t size, const char *fmt, va_l= ist args); __printf(3, 4) int scnprintf(char *buf, size_t size, const char *fmt, ...); __printf(3, 0) int vscnprintf(char *buf, size_t size, const char *fmt, va_= list args); +__printf(3, 4) char *seprintf(char *p, const char end[0], const char *fmt,= ...); +__printf(3, 0) char *vseprintf(char *p, const char end[0], const char *fmt= , va_list args); __printf(2, 3) __malloc char *kasprintf(gfp_t gfp, const char *fmt, ...); __printf(2, 0) __malloc char *kvasprintf(gfp_t gfp, const char *fmt, va_li= st args); __printf(2, 0) const char *kvasprintf_const(gfp_t gfp, const char *fmt, va= _list args); diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 01699852f30c..a3efacadb5e5 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -2892,6 +2892,37 @@ int vsnprintf(char *buf, size_t size, const char *fm= t_str, va_list args) } EXPORT_SYMBOL(vsnprintf); =20 +/** + * vstprintf - Format a string and place it in a buffer + * @buf: The buffer to place the result into + * @size: The size of the buffer, including the trailing null space + * @fmt: The format string to use + * @args: Arguments for the format string + * + * The return value is the length of the new string. + * If the string is truncated, the function returns -E2BIG. + * + * If you're not already dealing with a va_list consider using stprintf(). + * + * See the vsnprintf() documentation for format string extensions over C99. + */ +int vstprintf(char *buf, size_t size, const char *fmt, va_list args) +{ + int len; + + len =3D vsnprintf(buf, size, fmt, args); + + // It seems the kernel's vsnprintf() doesn't fail? + //if (unlikely(len < 0)) + // return -E2BIG; + + if (unlikely(len >=3D size)) + return -E2BIG; + + return len; +} +EXPORT_SYMBOL(vstprintf); + /** * vscnprintf - Format a string and place it in a buffer * @buf: The buffer to place the result into @@ -2923,6 +2954,36 @@ int vscnprintf(char *buf, size_t size, const char *f= mt, va_list args) } EXPORT_SYMBOL(vscnprintf); =20 +/** + * vseprintf - Format a string and place it in a buffer + * @p: The buffer to place the result into + * @end: A pointer to one past the last character in the buffer + * @fmt: The format string to use + * @args: Arguments for the format string + * + * The return value is a pointer to the trailing '\0'. + * If @p is NULL, the function returns NULL. + * If the string is truncated, the function returns NULL. + * + * If you're not already dealing with a va_list consider using seprintf(). + * + * See the vsnprintf() documentation for format string extensions over C99. + */ +char *vseprintf(char *p, const char end[0], const char *fmt, va_list args) +{ + int len; + + if (unlikely(p =3D=3D NULL)) + return NULL; + + len =3D vstprintf(p, end - p, fmt, args); + if (unlikely(len < 0)) + return NULL; + + return p + len; +} +EXPORT_SYMBOL(vseprintf); + /** * snprintf - Format a string and place it in a buffer * @buf: The buffer to place the result into @@ -2950,6 +3011,30 @@ int snprintf(char *buf, size_t size, const char *fmt= , ...) } EXPORT_SYMBOL(snprintf); =20 +/** + * stprintf - Format a string and place it in a buffer + * @buf: The buffer to place the result into + * @size: The size of the buffer, including the trailing null space + * @fmt: The format string to use + * @...: Arguments for the format string + * + * The return value is the length of the new string. + * If the string is truncated, the function returns -E2BIG. + */ + +int stprintf(char *buf, size_t size, const char *fmt, ...) +{ + va_list args; + int len; + + va_start(args, fmt); + len =3D vstprintf(buf, size, fmt, args); + va_end(args); + + return len; +} +EXPORT_SYMBOL(stprintf); + /** * scnprintf - Format a string and place it in a buffer * @buf: The buffer to place the result into @@ -2974,6 +3059,30 @@ int scnprintf(char *buf, size_t size, const char *fm= t, ...) } EXPORT_SYMBOL(scnprintf); =20 +/** + * seprintf - Format a string and place it in a buffer + * @p: The buffer to place the result into + * @end: A pointer to one past the last character in the buffer + * @fmt: The format string to use + * @...: Arguments for the format string + * + * The return value is a pointer to the trailing '\0'. + * If @buf is NULL, the function returns NULL. + * If the string is truncated, the function returns NULL. + */ + +char *seprintf(char *p, const char end[0], const char *fmt, ...) +{ + va_list args; + + va_start(args, fmt); + p =3D vseprintf(p, end, fmt, args); + va_end(args); + + return p; +} +EXPORT_SYMBOL(seprintf); + /** * vsprintf - Format a string and place it in a buffer * @buf: The buffer to place the result into --=20 2.50.0 From nobody Tue Oct 7 20:54:59 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AAC9B29E107; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="O+0fEEWh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1DB8BC4CEED; Sun, 6 Jul 2025 17:37:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751823458; bh=UnukMHnFrNRdetsFMcw3prQ/v4qlktaL9HMhPaNQEX0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=O+0fEEWh9MJ6JFKfYxoBMdO22bAvSQoipCY0TnxmtCAoa6FLL9qyOXFWbJGOj4EXo klJx55P/GGzG0UvTYhk7wyvwGE+iB1JWnE4v8f31Q0QUPccSmghsq1PZHDy4+IHCkB qY8GJgZlcUxBFWFhFL86qrDo3bzzfapdPvQCoaIKp6kIXkYcnWIpRCQ69JEY4XtQP9 3ZCl6wmRE2JxPtSI1pH4JlXEisY0sK4FHcIqgIGBp0TV/aS+YaxL67X9Nzh2Hw/Wpt jD0x+IZT/s4aq8rCGZ8e76I2nE3Fgrt728mxNrqGUkuYSu2ikDHqflY4owJ3sCl3HD 8uRGUvyKYqKTg== Date: Sun, 6 Jul 2025 19:37:36 +0200 From: Alejandro Colomar To: linux-mm@kvack.org, linux-hardening@vger.kernel.org Cc: Alejandro Colomar , Kees Cook , Christopher Bazley , shadow <~hallyn/shadow@lists.sr.ht>, linux-kernel@vger.kernel.org, Andrew Morton , kasan-dev@googlegroups.com, Dmitry Vyukov , Alexander Potapenko , Marco Elver , Christoph Lameter , David Rientjes , Vlastimil Babka , Roman Gushchin , Harry Yoo , Andrew Clayton Subject: [RFC v2 2/5] stacktrace, stackdepot: Add seprintf()-like variants of functions Message-ID: <9c140de9842dd34096928a7c87dab4f45ef18764.1751823326.git.alx@kernel.org> X-Mailer: git-send-email 2.50.0 References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" I think there's an anomaly in stack_depot_s*print(). If we have zero entries, we don't copy anything, which means the string is still not a string. Normally, this function is called surrounded by other calls to s*printf(), which guarantee that there's a '\0', but maybe we should make sure to write a '\0' here? Cc: Kees Cook Cc: Christopher Bazley Signed-off-by: Alejandro Colomar --- include/linux/stackdepot.h | 13 +++++++++++++ include/linux/stacktrace.h | 3 +++ kernel/stacktrace.c | 28 ++++++++++++++++++++++++++++ lib/stackdepot.c | 12 ++++++++++++ 4 files changed, 56 insertions(+) diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index 2cc21ffcdaf9..a7749fc3ac7c 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -219,6 +219,19 @@ void stack_depot_print(depot_stack_handle_t stack); int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t siz= e, int spaces); =20 +/** + * stack_depot_seprint - Print a stack trace from stack depot into a buffer + * + * @handle: Stack depot handle returned from stack_depot_save() + * @p: Pointer to the print buffer + * @end: Pointer to one past the last element in the buffer + * @spaces: Number of leading spaces to print + * + * Return: Pointer to trailing '\0'; or NULL on truncation + */ +char *stack_depot_seprint(depot_stack_handle_t handle, char *p, + const char end[0], int spaces); + /** * stack_depot_put - Drop a reference to a stack trace from stack depot * diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h index 97455880ac41..748936386c89 100644 --- a/include/linux/stacktrace.h +++ b/include/linux/stacktrace.h @@ -67,6 +67,9 @@ void stack_trace_print(const unsigned long *trace, unsign= ed int nr_entries, int spaces); int stack_trace_snprint(char *buf, size_t size, const unsigned long *entri= es, unsigned int nr_entries, int spaces); +char *stack_trace_seprint(char *p, const char end[0], + const unsigned long *entries, unsigned int nr_entries, + int spaces); unsigned int stack_trace_save(unsigned long *store, unsigned int size, unsigned int skipnr); unsigned int stack_trace_save_tsk(struct task_struct *task, diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index afb3c116da91..65caf9e63673 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -70,6 +70,34 @@ int stack_trace_snprint(char *buf, size_t size, const un= signed long *entries, } EXPORT_SYMBOL_GPL(stack_trace_snprint); =20 +/** + * stack_trace_seprint - Print the entries in the stack trace into a buffer + * @p: Pointer to the print buffer + * @end: Pointer to one past the last element in the buffer + * @entries: Pointer to storage array + * @nr_entries: Number of entries in the storage array + * @spaces: Number of leading spaces to print + * + * Return: Pointer to the trailing '\0'; or NULL on truncation. + */ +char *stack_trace_seprint(char *p, const char end[0], + const unsigned long *entries, unsigned int nr_entries, + int spaces) +{ + unsigned int i; + + if (WARN_ON(!entries)) + return 0; + + for (i =3D 0; i < nr_entries; i++) { + p =3D seprintf(p, end, "%*c%pS\n", 1 + spaces, ' ', + (void *)entries[i]); + } + + return p; +} +EXPORT_SYMBOL_GPL(stack_trace_seprint); + #ifdef CONFIG_ARCH_STACKWALK =20 struct stacktrace_cookie { diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 73d7b50924ef..749496e6a6f1 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -771,6 +771,18 @@ int stack_depot_snprint(depot_stack_handle_t handle, c= har *buf, size_t size, } EXPORT_SYMBOL_GPL(stack_depot_snprint); =20 +char *stack_depot_seprint(depot_stack_handle_t handle, char *p, + const char end[0], int spaces) +{ + unsigned long *entries; + unsigned int nr_entries; + + nr_entries =3D stack_depot_fetch(handle, &entries); + return nr_entries ? stack_trace_seprint(p, end, entries, nr_entries, + spaces) : p; +} +EXPORT_SYMBOL_GPL(stack_depot_seprint); + depot_stack_handle_t __must_check stack_depot_set_extra_bits( depot_stack_handle_t handle, unsigned int extra_bits) { --=20 2.50.0 From nobody Tue Oct 7 20:54:59 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C572929E11B; Sun, 6 Jul 2025 17:37:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751823460; cv=none; b=TNVB5GIrDhF7rLb1W7D+f5amlkMIsiKhswVq0VIP8We8RKgWawISKobt6q+cO1Vv6zWBEboSuhe9qIBQyAN4VJLItlVB3CzHJIa7K6Bwr6mi5aPGGU0zXuMqMD2MJz701hAOeBhnNexj64w5IiO7Zt4qCyCId9x8OghTVMaZArk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751823460; c=relaxed/simple; bh=EOC8hc/se0MHRZ8SrRfccouU5lvaqaEihSZqCN2Z/O0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=BvLWO0LVZNq+JD2L6mdZgYTMY8pZ8J1XxJQEyxw+JxVNVpe+460+R2SLHkDVSqrxz8epS9MiSNGfNsQy+8O1G5aZzEwTnCC3BhAtIXilEI8v17bVBh2B8osrtR633SNsJM5G1khsw1TBnJkDmMTGn7Mm1D0p8/Aey7OOOcMYkrY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=g1weyM3h; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="g1weyM3h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34891C4CEEE; Sun, 6 Jul 2025 17:37:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751823460; bh=EOC8hc/se0MHRZ8SrRfccouU5lvaqaEihSZqCN2Z/O0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=g1weyM3hNVPu0/1x16f9Mt8C8UeDTBQK+dyY7SRq0JFMah2iy9UbTB4dMkJpKRNmv AHl5PkWOt+XiXoXDcJqlKdizIYlrPWQcnTIjVn5WRVhhXaKolHRdlqAxamQgXAwGBT KtV9WV7MCGqGIp1IEhZY1mQJi7eHof0+bsJKrQnQoA2unlX79nw4lY6nE7CaBDVABB cneEqaPcStmGCHrE7MMbXPjM8SVMcXyiXQKvaER04YM6/ZYAjxe821pgoovXYEWF8I fE+Na4z2bLIbgmLxWZ2qGQXMIcIEz7Jez7WEM9wmQ89gWygknYwxHo+moxgARji0Rf tloCrZBoTosUw== Date: Sun, 6 Jul 2025 19:37:38 +0200 From: Alejandro Colomar To: linux-mm@kvack.org, linux-hardening@vger.kernel.org Cc: Alejandro Colomar , Kees Cook , Christopher Bazley , shadow <~hallyn/shadow@lists.sr.ht>, linux-kernel@vger.kernel.org, Andrew Morton , kasan-dev@googlegroups.com, Dmitry Vyukov , Alexander Potapenko , Marco Elver , Christoph Lameter , David Rientjes , Vlastimil Babka , Roman Gushchin , Harry Yoo , Andrew Clayton Subject: [RFC v2 3/5] mm: Use seprintf() instead of less ergonomic APIs Message-ID: X-Mailer: git-send-email 2.50.0 References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" While doing this, I detected some anomalies in the existing code: mm/kfence/kfence_test.c: - The last call to scnprintf() did increment 'cur', but it's unused after that, so it was dead code. I've removed the dead code in this patch. - 'end' is calculated as end =3D &expect[0][sizeof(expect[0] - 1)]; However, the '-1' doesn't seem to be necessary. When passing $2 to scnprintf(), the size was specified as 'end - cur'. And scnprintf() --just like snprintf(3)--, won't write more than $2 bytes (including the null byte). That means that scnprintf() wouldn't write more than &expect[0][sizeof(expect[0]) - 1] - expect[0] which simplifies to sizeof(expect[0]) - 1 bytes. But we have sizeof(expect[0]) bytes available, so we're wasting one byte entirely. This is a benign off-by-one bug. The two occurrences of this bug will be fixed in a following patch in this series. mm/kmsan/kmsan_test.c: The same benign off-by-one bug calculating the remaining size. mm/mempolicy.c: This file uses the 'p +=3D snprintf()' anti-pattern. That will overflow the pointer on truncation, which has undefined behavior. Using seprintf(), this bug is fixed. As in the previous file, here there was also dead code in the last scnprintf() call, by incrementing a pointer that is not used after the call. I've removed the dead code. mm/page_owner.c: Within print_page_owner(), there are some calls to scnprintf(), which do report truncation. And then there are other calls to snprintf(), where we handle errors (there are two 'goto err'). I've kept the existing error handling, as I trust it's there for a good reason (i.e., we may want to avoid calling print_page_owner_memcg() if we truncated before). Please review if this amount of error handling is the right one, or if we want to add or remove some. For seprintf(), a single test for null after the last call is enough to detect truncation. mm/slub.c: Again, the 'p +=3D snprintf()' anti-pattern. This is UB, and by using seprintf() we've fixed the bug. Cc: Kees Cook Cc: Christopher Bazley Signed-off-by: Alejandro Colomar --- mm/kfence/kfence_test.c | 24 ++++++++++++------------ mm/kmsan/kmsan_test.c | 4 ++-- mm/mempolicy.c | 18 +++++++++--------- mm/page_owner.c | 32 +++++++++++++++++--------------- mm/slub.c | 5 +++-- 5 files changed, 43 insertions(+), 40 deletions(-) diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c index 00034e37bc9f..ff734c514c03 100644 --- a/mm/kfence/kfence_test.c +++ b/mm/kfence/kfence_test.c @@ -113,26 +113,26 @@ static bool report_matches(const struct expect_report= *r) end =3D &expect[0][sizeof(expect[0]) - 1]; switch (r->type) { case KFENCE_ERROR_OOB: - cur +=3D scnprintf(cur, end - cur, "BUG: KFENCE: out-of-bounds %s", + cur =3D seprintf(cur, end, "BUG: KFENCE: out-of-bounds %s", get_access_type(r)); break; case KFENCE_ERROR_UAF: - cur +=3D scnprintf(cur, end - cur, "BUG: KFENCE: use-after-free %s", + cur =3D seprintf(cur, end, "BUG: KFENCE: use-after-free %s", get_access_type(r)); break; case KFENCE_ERROR_CORRUPTION: - cur +=3D scnprintf(cur, end - cur, "BUG: KFENCE: memory corruption"); + cur =3D seprintf(cur, end, "BUG: KFENCE: memory corruption"); break; case KFENCE_ERROR_INVALID: - cur +=3D scnprintf(cur, end - cur, "BUG: KFENCE: invalid %s", + cur =3D seprintf(cur, end, "BUG: KFENCE: invalid %s", get_access_type(r)); break; case KFENCE_ERROR_INVALID_FREE: - cur +=3D scnprintf(cur, end - cur, "BUG: KFENCE: invalid free"); + cur =3D seprintf(cur, end, "BUG: KFENCE: invalid free"); break; } =20 - scnprintf(cur, end - cur, " in %pS", r->fn); + seprintf(cur, end, " in %pS", r->fn); /* The exact offset won't match, remove it; also strip module name. */ cur =3D strchr(expect[0], '+'); if (cur) @@ -144,26 +144,26 @@ static bool report_matches(const struct expect_report= *r) =20 switch (r->type) { case KFENCE_ERROR_OOB: - cur +=3D scnprintf(cur, end - cur, "Out-of-bounds %s at", get_access_typ= e(r)); + cur =3D seprintf(cur, end, "Out-of-bounds %s at", get_access_type(r)); addr =3D arch_kfence_test_address(addr); break; case KFENCE_ERROR_UAF: - cur +=3D scnprintf(cur, end - cur, "Use-after-free %s at", get_access_ty= pe(r)); + cur =3D seprintf(cur, end, "Use-after-free %s at", get_access_type(r)); addr =3D arch_kfence_test_address(addr); break; case KFENCE_ERROR_CORRUPTION: - cur +=3D scnprintf(cur, end - cur, "Corrupted memory at"); + cur =3D seprintf(cur, end, "Corrupted memory at"); break; case KFENCE_ERROR_INVALID: - cur +=3D scnprintf(cur, end - cur, "Invalid %s at", get_access_type(r)); + cur =3D seprintf(cur, end, "Invalid %s at", get_access_type(r)); addr =3D arch_kfence_test_address(addr); break; case KFENCE_ERROR_INVALID_FREE: - cur +=3D scnprintf(cur, end - cur, "Invalid free of"); + cur =3D seprintf(cur, end, "Invalid free of"); break; } =20 - cur +=3D scnprintf(cur, end - cur, " 0x%p", (void *)addr); + seprintf(cur, end, " 0x%p", (void *)addr); =20 spin_lock_irqsave(&observed.lock, flags); if (!report_available()) diff --git a/mm/kmsan/kmsan_test.c b/mm/kmsan/kmsan_test.c index 9733a22c46c1..a062a46b2d24 100644 --- a/mm/kmsan/kmsan_test.c +++ b/mm/kmsan/kmsan_test.c @@ -107,9 +107,9 @@ static bool report_matches(const struct expect_report *= r) cur =3D expected_header; end =3D &expected_header[sizeof(expected_header) - 1]; =20 - cur +=3D scnprintf(cur, end - cur, "BUG: KMSAN: %s", r->error_type); + cur =3D seprintf(cur, end, "BUG: KMSAN: %s", r->error_type); =20 - scnprintf(cur, end - cur, " in %s", r->symbol); + seprintf(cur, end, " in %s", r->symbol); /* The exact offset won't match, remove it; also strip module name. */ cur =3D strchr(expected_header, '+'); if (cur) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index b28a1e6ae096..c696e4a6f4c2 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -3359,6 +3359,7 @@ int mpol_parse_str(char *str, struct mempolicy **mpol) void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol) { char *p =3D buffer; + char *e =3D buffer + maxlen; nodemask_t nodes =3D NODE_MASK_NONE; unsigned short mode =3D MPOL_DEFAULT; unsigned short flags =3D 0; @@ -3384,33 +3385,32 @@ void mpol_to_str(char *buffer, int maxlen, struct m= empolicy *pol) break; default: WARN_ON_ONCE(1); - snprintf(p, maxlen, "unknown"); + seprintf(p, e, "unknown"); return; } =20 - p +=3D snprintf(p, maxlen, "%s", policy_modes[mode]); + p =3D seprintf(p, e, "%s", policy_modes[mode]); =20 if (flags & MPOL_MODE_FLAGS) { - p +=3D snprintf(p, buffer + maxlen - p, "=3D"); + p =3D seprintf(p, e, "=3D"); =20 /* * Static and relative are mutually exclusive. */ if (flags & MPOL_F_STATIC_NODES) - p +=3D snprintf(p, buffer + maxlen - p, "static"); + p =3D seprintf(p, e, "static"); else if (flags & MPOL_F_RELATIVE_NODES) - p +=3D snprintf(p, buffer + maxlen - p, "relative"); + p =3D seprintf(p, e, "relative"); =20 if (flags & MPOL_F_NUMA_BALANCING) { if (!is_power_of_2(flags & MPOL_MODE_FLAGS)) - p +=3D snprintf(p, buffer + maxlen - p, "|"); - p +=3D snprintf(p, buffer + maxlen - p, "balancing"); + p =3D seprintf(p, e, "|"); + p =3D seprintf(p, e, "balancing"); } } =20 if (!nodes_empty(nodes)) - p +=3D scnprintf(p, buffer + maxlen - p, ":%*pbl", - nodemask_pr_args(&nodes)); + seprintf(p, e, ":%*pbl", nodemask_pr_args(&nodes)); } =20 #ifdef CONFIG_SYSFS diff --git a/mm/page_owner.c b/mm/page_owner.c index cc4a6916eec6..5811738e3320 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -496,7 +496,7 @@ void pagetypeinfo_showmixedcount_print(struct seq_file = *m, /* * Looking for memcg information and print it out */ -static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret, +static inline char *print_page_owner_memcg(char *p, const char end[0], struct page *page) { #ifdef CONFIG_MEMCG @@ -511,8 +511,7 @@ static inline int print_page_owner_memcg(char *kbuf, si= ze_t count, int ret, goto out_unlock; =20 if (memcg_data & MEMCG_DATA_OBJEXTS) - ret +=3D scnprintf(kbuf + ret, count - ret, - "Slab cache page\n"); + p =3D seprintf(p, end, "Slab cache page\n"); =20 memcg =3D page_memcg_check(page); if (!memcg) @@ -520,7 +519,7 @@ static inline int print_page_owner_memcg(char *kbuf, si= ze_t count, int ret, =20 online =3D (memcg->css.flags & CSS_ONLINE); cgroup_name(memcg->css.cgroup, name, sizeof(name)); - ret +=3D scnprintf(kbuf + ret, count - ret, + p =3D seprintf(p, end, "Charged %sto %smemcg %s\n", PageMemcgKmem(page) ? "(via objcg) " : "", online ? "" : "offline ", @@ -529,7 +528,7 @@ static inline int print_page_owner_memcg(char *kbuf, si= ze_t count, int ret, rcu_read_unlock(); #endif /* CONFIG_MEMCG */ =20 - return ret; + return p; } =20 static ssize_t @@ -538,14 +537,16 @@ print_page_owner(char __user *buf, size_t count, unsi= gned long pfn, depot_stack_handle_t handle) { int ret, pageblock_mt, page_mt; - char *kbuf; + char *kbuf, *p, *e; =20 count =3D min_t(size_t, count, PAGE_SIZE); kbuf =3D kmalloc(count, GFP_KERNEL); if (!kbuf) return -ENOMEM; =20 - ret =3D scnprintf(kbuf, count, + p =3D kbuf; + e =3D kbuf + count; + p =3D seprintf(p, e, "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts = %llu ns\n", page_owner->order, page_owner->gfp_mask, &page_owner->gfp_mask, page_owner->pid, @@ -555,7 +556,7 @@ print_page_owner(char __user *buf, size_t count, unsign= ed long pfn, /* Print information relevant to grouping pages by mobility */ pageblock_mt =3D get_pageblock_migratetype(page); page_mt =3D gfp_migratetype(page_owner->gfp_mask); - ret +=3D scnprintf(kbuf + ret, count - ret, + p =3D seprintf(p, e, "PFN 0x%lx type %s Block %lu type %s Flags %pGp\n", pfn, migratetype_names[page_mt], @@ -563,22 +564,23 @@ print_page_owner(char __user *buf, size_t count, unsi= gned long pfn, migratetype_names[pageblock_mt], &page->flags); =20 - ret +=3D stack_depot_snprint(handle, kbuf + ret, count - ret, 0); - if (ret >=3D count) - goto err; + p =3D stack_depot_seprint(handle, p, e, 0); + if (p =3D=3D NULL) + goto err; // XXX: Should we remove this error handling? =20 if (page_owner->last_migrate_reason !=3D -1) { - ret +=3D scnprintf(kbuf + ret, count - ret, + p =3D seprintf(p, e, "Page has been migrated, last migrate reason: %s\n", migrate_reason_names[page_owner->last_migrate_reason]); } =20 - ret =3D print_page_owner_memcg(kbuf, count, ret, page); + p =3D print_page_owner_memcg(p, e, page); =20 - ret +=3D snprintf(kbuf + ret, count - ret, "\n"); - if (ret >=3D count) + p =3D seprintf(p, e, "\n"); + if (p =3D=3D NULL) goto err; =20 + ret =3D p - kbuf; if (copy_to_user(buf, kbuf, ret)) ret =3D -EFAULT; =20 diff --git a/mm/slub.c b/mm/slub.c index be8b09e09d30..b67c6ca0d0f7 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -7451,6 +7451,7 @@ static char *create_unique_id(struct kmem_cache *s) { char *name =3D kmalloc(ID_STR_LENGTH, GFP_KERNEL); char *p =3D name; + char *e =3D name + ID_STR_LENGTH; =20 if (!name) return ERR_PTR(-ENOMEM); @@ -7475,9 +7476,9 @@ static char *create_unique_id(struct kmem_cache *s) *p++ =3D 'A'; if (p !=3D name + 1) *p++ =3D '-'; - p +=3D snprintf(p, ID_STR_LENGTH - (p - name), "%07u", s->size); + p =3D seprintf(p, e, "%07u", s->size); =20 - if (WARN_ON(p > name + ID_STR_LENGTH - 1)) { + if (WARN_ON(p =3D=3D NULL)) { kfree(name); return ERR_PTR(-EINVAL); } --=20 2.50.0 From nobody Tue Oct 7 20:54:59 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1D68029E107; Sun, 6 Jul 2025 17:37:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751823463; cv=none; b=uWOhtdhhPxNRnWO6vVKiEHhVrIoh7dwqdIXxfWI1ORzOEO4ixBSFOETzcV7KD1/GGmotJgHWWD9u58aobG5uLsdqNDLpKFHsuxTwO6GPcaoBuYUCZZ4UpK+FJqAT5YtgY/eLXLZ7+4v1GWJLtzrrhCVL0qWfax8exwtNBxvSVew= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751823463; c=relaxed/simple; bh=qe0OTWsYjimAaCK25tMmk1gW7skbsmCkZX6Pukik9B8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=iP0dyZzCRe4vrpB/6LyfwNXKEoTBycHZ+lB3MLK5ToRKeyt7qGf/Y0XGNrI5X6d/gLwccwWLS6ecZAacrczNUGPgd0NIPu4SL1xKc0BtvPVvVCgF86D+DVibY0nyHNBE91Cmu51eMr+6hbUiQAB7ivx5K2YYHoFziT2vON70qRw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XlbC7Oy6; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XlbC7Oy6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D26BC4CEED; Sun, 6 Jul 2025 17:37:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751823462; bh=qe0OTWsYjimAaCK25tMmk1gW7skbsmCkZX6Pukik9B8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XlbC7Oy64OfgfN20MltOgEUEHqTitA9SuofjL4lDG65XV+5PVcmB9Zw5FVIt8dL07 Cc8du/YegNQQeQbak5aEtboc5EzuTi4pTg+dDK20UeJW03Th3PpbGVThPgoyZmKkAM TctPUlTtRWV8W4KHz/hGLXuJCusFkwYf7gylZep6L6MNnP8BDQV3byTmz8yLhSWgj7 yjOqJ6BH1n8xa8j7sYfMLCAjfvYXr9OpJVFqQZ+7Tj5cC2tSGTFGADC81eG01tVLNv Ok1wlq7MeL+90JMGdMX4ndUeEkyEOPskd+wOAg8wDKdblO0emOLXX8L0dNnNiPwS1M pO88YarNbIyVQ== Date: Sun, 6 Jul 2025 19:37:40 +0200 From: Alejandro Colomar To: linux-mm@kvack.org, linux-hardening@vger.kernel.org Cc: Alejandro Colomar , Kees Cook , Christopher Bazley , shadow <~hallyn/shadow@lists.sr.ht>, linux-kernel@vger.kernel.org, Andrew Morton , kasan-dev@googlegroups.com, Dmitry Vyukov , Alexander Potapenko , Marco Elver , Christoph Lameter , David Rientjes , Vlastimil Babka , Roman Gushchin , Harry Yoo , Andrew Clayton Subject: [RFC v2 4/5] array_size.h: Add ENDOF() Message-ID: <5331d286ceca807bab76587127a9491c807c9a2a.1751823326.git.alx@kernel.org> X-Mailer: git-send-email 2.50.0 References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This macro is useful to calculate the second argument to seprintf(), avoiding off-by-one bugs. Cc: Kees Cook Cc: Christopher Bazley Signed-off-by: Alejandro Colomar --- include/linux/array_size.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/include/linux/array_size.h b/include/linux/array_size.h index 06d7d83196ca..a743d4ad5911 100644 --- a/include/linux/array_size.h +++ b/include/linux/array_size.h @@ -10,4 +10,10 @@ */ #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(= arr)) =20 +/** + * ENDOF - get a pointer to one past the last element in array @arr + * @arr: array + */ +#define ENDOF(a) (a + ARRAY_SIZE(a)) + #endif /* _LINUX_ARRAY_SIZE_H */ --=20 2.50.0 From nobody Tue Oct 7 20:54:59 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 59F022BD590; Sun, 6 Jul 2025 17:37:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751823465; cv=none; b=i0z7NxAYizgC4xocyVlpW6GLfueo9p5LNi/q9ExO3DTwXWEpuXd/OWVfdTbW9I7/AH5pKqtIcxrpEiR14f7kIfva+N8dDWpN4a2XSKfCuTig7CUXk62IjogL3+jL9HhWzyQ+jAwn0YHaEQqc5CQU2O70gPqv6ZmfdKIHfVTA64w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751823465; c=relaxed/simple; bh=y/NagA9ATWYzQCU9rSacENdhdRjkHrBaR2aM75AXuY4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=dnO+Apl5cR/J/b0tGe+1LyQm5sDSybCnFiwNZSm7m6pbKJnQouJ/ptZreXnRF5qLpTOZSWBUNWCjTGWe5G5ik4PCRMTGHbyxhS6KZmlHu+ROMoFmcDH2xZOml2C1mdtQAPF3bYaTJYSJYLsvEhmdIIkw7jF87gGuUE/TXOXhdEo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=orXVAk+F; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="orXVAk+F" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C8C44C4CEF2; Sun, 6 Jul 2025 17:37:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751823464; bh=y/NagA9ATWYzQCU9rSacENdhdRjkHrBaR2aM75AXuY4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=orXVAk+FU306mzqc4WhNNGyh/QPVlsfnq/ha7OFRjsYJOwSW73KjZW8tCUBpZgyDP mbORBDmTYFZkpLbehJgkJhLq/4ZCIXhjynSsAGwf0EqUWpnGo/Muxyl1CI90UJJKtj ezTaWG8VARDp4Moj71p1hYDbGgLV4RsFLq2LjYpilvFJoDjIE/TwQ1q+qt20QQdgxw JBWIvDsbrB7vbp7xFHVyRLxEANRyUi9+tRBHqj0kmmt5xyTInSbKrGqGtdo4VNYKQl wEZTKnNAeDUvtJTb5fRkixKidZjrtzA220veml1DsWHOnnKWfa5unpoP4QXeKE64pL Mn9V6k6yePUzw== Date: Sun, 6 Jul 2025 19:37:42 +0200 From: Alejandro Colomar To: linux-mm@kvack.org, linux-hardening@vger.kernel.org Cc: Alejandro Colomar , Kees Cook , Christopher Bazley , shadow <~hallyn/shadow@lists.sr.ht>, linux-kernel@vger.kernel.org, Andrew Morton , kasan-dev@googlegroups.com, Dmitry Vyukov , Alexander Potapenko , Marco Elver , Christoph Lameter , David Rientjes , Vlastimil Babka , Roman Gushchin , Harry Yoo , Andrew Clayton Subject: [RFC v2 5/5] mm: Fix benign off-by-one bugs Message-ID: <08cfdd2bf77911ca6ce3c0b6c310daea77eb307a.1751823326.git.alx@kernel.org> X-Mailer: git-send-email 2.50.0 References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" We were wasting a byte due to an off-by-one bug. s[c]nprintf() doesn't write more than $2 bytes including the null byte, so trying to pass 'size-1' there is wasting one byte. Now that we use seprintf(), the situation isn't different: seprintf() will stop writing *before* 'end' --that is, at most the terminating null byte will be written at 'end-1'--. Cc: Kees Cook Cc: Christopher Bazley Signed-off-by: Alejandro Colomar --- mm/kfence/kfence_test.c | 4 ++-- mm/kmsan/kmsan_test.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c index ff734c514c03..f02c3e23638a 100644 --- a/mm/kfence/kfence_test.c +++ b/mm/kfence/kfence_test.c @@ -110,7 +110,7 @@ static bool report_matches(const struct expect_report *= r) =20 /* Title */ cur =3D expect[0]; - end =3D &expect[0][sizeof(expect[0]) - 1]; + end =3D ENDOF(expect[0]); switch (r->type) { case KFENCE_ERROR_OOB: cur =3D seprintf(cur, end, "BUG: KFENCE: out-of-bounds %s", @@ -140,7 +140,7 @@ static bool report_matches(const struct expect_report *= r) =20 /* Access information */ cur =3D expect[1]; - end =3D &expect[1][sizeof(expect[1]) - 1]; + end =3D ENDOF(expect[1]); =20 switch (r->type) { case KFENCE_ERROR_OOB: diff --git a/mm/kmsan/kmsan_test.c b/mm/kmsan/kmsan_test.c index a062a46b2d24..882500807db8 100644 --- a/mm/kmsan/kmsan_test.c +++ b/mm/kmsan/kmsan_test.c @@ -105,7 +105,7 @@ static bool report_matches(const struct expect_report *= r) =20 /* Title */ cur =3D expected_header; - end =3D &expected_header[sizeof(expected_header) - 1]; + end =3D ENDOF(expected_header); =20 cur =3D seprintf(cur, end, "BUG: KMSAN: %s", r->error_type); =20 --=20 2.50.0