From: Matteo Croce <mcroce@linux.microsoft.com>
To: linux-kernel@vger.kernel.org
Cc: Guenter Roeck <linux@roeck-us.net>,
Petr Mladek <pmladek@suse.com>, Arnd Bergmann <arnd@arndb.de>,
Mike Rapoport <rppt@kernel.org>,
Kees Cook <keescook@chromium.org>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Robin Holt <robinmholt@gmail.com>,
Fabian Frederick <fabf@skynet.be>,
stable@vger.kernel.org
Subject: [PATCH 2/2] reboot: fix parsing of reboot cpu number
Date: Fri, 16 Oct 2020 20:09:07 +0200 [thread overview]
Message-ID: <20201016180907.171957-3-mcroce@linux.microsoft.com> (raw)
In-Reply-To: <20201016180907.171957-1-mcroce@linux.microsoft.com>
From: Matteo Croce <mcroce@microsoft.com>
The kernel cmdline reboot= argument allows to specify the CPU used
for rebooting, with the syntax `s####` among the other flags, e.g.
reboot=soft,s4
reboot=warm,s31,force
In the early days the parsing was done with simple_strtoul(), later
deprecated in favor of the safer kstrtoint() which handles overflow.
But kstrtoint() returns -EINVAL if there are non-digit characters
in a string, so if this flag is not the last given, it's silently
ignored as well as the subsequent ones.
To fix it, revert the usage of simple_strtoul(), which is no longer
deprecated, and restore the old behaviour.
While at it, merge two identical code blocks into one.
Fixes: 616feab75397 ("kernel/reboot.c: convert simple_strtoul to kstrtoint")
Signed-off-by: Matteo Croce <mcroce@microsoft.com>
---
kernel/reboot.c | 30 ++++++++++++------------------
1 file changed, 12 insertions(+), 18 deletions(-)
diff --git a/kernel/reboot.c b/kernel/reboot.c
index c4e7965c39b9..475f790bbd75 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -552,25 +552,19 @@ static int __init reboot_setup(char *str)
case 's':
{
- int rc;
-
- if (isdigit(*(str+1))) {
- rc = kstrtoint(str+1, 0, &reboot_cpu);
- if (rc)
- return rc;
- if (reboot_cpu >= num_possible_cpus()) {
- reboot_cpu = 0;
- return -ERANGE;
- }
- } else if (str[1] == 'm' && str[2] == 'p' &&
- isdigit(*(str+3))) {
- rc = kstrtoint(str+3, 0, &reboot_cpu);
- if (rc)
- return rc;
- if (reboot_cpu >= num_possible_cpus()) {
- reboot_cpu = 0;
+ int cpu;
+
+ /*
+ * reboot_cpu is s[mp]#### with #### being the processor
+ * to be used for rebooting. Skip 's' or 'smp' prefix.
+ */
+ str += str[1] == 'm' && str[2] == 'p' ? 3 : 1;
+
+ if (isdigit(str[0])) {
+ cpu = simple_strtoul(str, NULL, 10);
+ if (cpu >= num_possible_cpus())
return -ERANGE;
- }
+ reboot_cpu = cpu;
} else
*mode = REBOOT_SOFT;
break;
--
2.26.2
next prev parent reply other threads:[~2020-10-16 18:09 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-16 18:09 [PATCH 0/2] fix parsing of reboot= cmdline Matteo Croce
2020-10-16 18:09 ` [PATCH 1/2] reboot: fix overflow parsing reboot cpu number Matteo Croce
2020-10-16 19:25 ` Kees Cook
2020-10-16 19:45 ` Pavel Tatashin
2020-10-19 13:18 ` Petr Mladek
2020-10-16 18:09 ` Matteo Croce [this message]
2020-10-16 19:26 ` [PATCH 2/2] reboot: fix parsing of " Kees Cook
2020-10-16 21:34 ` Matteo Croce
2020-10-16 19:46 ` Pavel Tatashin
2020-10-19 13:49 ` Petr Mladek
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