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| author | Sven Schnelle <svens@linux.ibm.com> | 2021-06-15 15:05:22 +0200 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2021-06-21 11:19:18 +0200 |
| commit | 9e3d62d55bf455d4f9fdf2ede5c8756410c64102 (patch) | |
| tree | aaf22e51576329f329311b7b9d077da19e5143d3 /arch | |
| parent | s390/vfio-ap: clean up mdev resources when remove callback invoked (diff) | |
| download | linux-9e3d62d55bf455d4f9fdf2ede5c8756410c64102.tar.xz linux-9e3d62d55bf455d4f9fdf2ede5c8756410c64102.zip | |
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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/s390/kernel/topology.c | 12 |
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); |