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;