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 v2 2/2] reboot: fix parsing of reboot cpu number
Date: Tue, 27 Oct 2020 14:35:45 +0100 [thread overview]
Message-ID: <20201027133545.58625-3-mcroce@linux.microsoft.com> (raw)
In-Reply-To: <20201027133545.58625-1-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..a09c5937c0b6 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, 0);
+ if (cpu >= num_possible_cpus())
return -ERANGE;
- }
+ reboot_cpu = cpu;
} else
*mode = REBOOT_SOFT;
break;
--
2.28.0
next prev parent reply other threads:[~2020-10-27 13:36 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 13:35 [PATCH v2 0/2] fix parsing of reboot= cmdline Matteo Croce
2020-10-27 13:35 ` [PATCH v2 1/2] reboot: fix overflow parsing reboot cpu number Matteo Croce
2020-10-27 13:42 ` Greg KH
2020-10-30 14:13 ` Petr Mladek
2020-10-30 14:18 ` Matteo Croce
2020-10-27 13:35 ` Matteo Croce [this message]
2020-10-27 13:42 ` [PATCH v2 2/2] reboot: fix parsing of " Greg KH
2020-10-30 14:30 ` Petr Mladek
2020-11-01 1:57 ` Matteo Croce
2020-11-02 11:01 ` Petr Mladek
2020-11-03 11:43 ` Matteo Croce
2020-11-03 14:25 ` Petr Mladek
2020-11-03 15:43 ` Matteo Croce
2020-11-03 16:22 ` Petr Mladek
2020-10-27 13:42 ` [PATCH v2 0/2] fix parsing of reboot= cmdline Greg KH
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