summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorSven Schnelle <svens@linux.ibm.com>2021-06-15 15:05:22 +0200
committerVasily Gorbik <gor@linux.ibm.com>2021-06-21 11:19:18 +0200
commit9e3d62d55bf455d4f9fdf2ede5c8756410c64102 (patch)
treeaaf22e51576329f329311b7b9d077da19e5143d3
parent8c0795d2a0f50e2b131f5b2a8c2795939a94058e (diff)
s390/topology: clear thread/group maps for offline cpus
The current code doesn't clear the thread/group maps for offline CPUs. This may cause kernel crashes like the one bewlow in common code that assumes if a CPU has sibblings it is online. Unable to handle kernel pointer dereference in virtual kernel address space Call Trace: [<000000013a4b8c3c>] blk_mq_map_swqueue+0x10c/0x388 ([<000000013a4b8bcc>] blk_mq_map_swqueue+0x9c/0x388) [<000000013a4b9300>] blk_mq_init_allocated_queue+0x448/0x478 [<000000013a4b9416>] blk_mq_init_queue+0x4e/0x90 [<000003ff8019d3e6>] loop_add+0x106/0x278 [loop] [<000003ff801b8148>] loop_init+0x148/0x1000 [loop] [<0000000139de4924>] do_one_initcall+0x3c/0x1e0 [<0000000139ef449a>] do_init_module+0x6a/0x2a0 [<0000000139ef61bc>] __do_sys_finit_module+0xa4/0xc0 [<0000000139de9e6e>] do_syscall+0x7e/0xd0 [<000000013a8e0aec>] __do_syscall+0xbc/0x110 [<000000013a8ee2e8>] system_call+0x78/0xa0 Fixes: 52aeda7accb6 ("s390/topology: remove offline CPUs from CPU topology masks") Cc: <stable@kernel.org> # 5.7+ Reported-by: Marius Hillenbrand <mhillen@linux.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
-rw-r--r--arch/s390/kernel/topology.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
index bfcc327acc6b..26aa2614ee35 100644
--- a/arch/s390/kernel/topology.c
+++ b/arch/s390/kernel/topology.c
@@ -66,7 +66,10 @@ static void cpu_group_map(cpumask_t *dst, struct mask_info *info, unsigned int c
{
static cpumask_t mask;
- cpumask_copy(&mask, cpumask_of(cpu));
+ cpumask_clear(&mask);
+ if (!cpu_online(cpu))
+ goto out;
+ cpumask_set_cpu(cpu, &mask);
switch (topology_mode) {
case TOPOLOGY_MODE_HW:
while (info) {
@@ -83,10 +86,10 @@ static void cpu_group_map(cpumask_t *dst, struct mask_info *info, unsigned int c
default:
fallthrough;
case TOPOLOGY_MODE_SINGLE:
- cpumask_copy(&mask, cpumask_of(cpu));
break;
}
cpumask_and(&mask, &mask, cpu_online_mask);
+out:
cpumask_copy(dst, &mask);
}
@@ -95,7 +98,10 @@ static void cpu_thread_map(cpumask_t *dst, unsigned int cpu)
static cpumask_t mask;
int i;
- cpumask_copy(&mask, cpumask_of(cpu));
+ cpumask_clear(&mask);
+ if (!cpu_online(cpu))
+ goto out;
+ cpumask_set_cpu(cpu, &mask);
if (topology_mode != TOPOLOGY_MODE_HW)
goto out;
cpu -= cpu % (smp_cpu_mtid + 1);