From 894c9ef9780c5cf2f143415e867ee39a33ecb75d Mon Sep 17 00:00:00 2001 From: Daniel Jordan Date: Tue, 3 Dec 2019 14:31:10 -0500 Subject: padata: validate cpumask without removed CPU during offline Configuring an instance's parallel mask without any online CPUs... echo 2 > /sys/kernel/pcrypt/pencrypt/parallel_cpumask echo 0 > /sys/devices/system/cpu/cpu1/online ...makes tcrypt mode=215 crash like this: divide error: 0000 [#1] SMP PTI CPU: 4 PID: 283 Comm: modprobe Not tainted 5.4.0-rc8-padata-doc-v2+ #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20191013_105130-anatol 04/01/2014 RIP: 0010:padata_do_parallel+0x114/0x300 Call Trace: pcrypt_aead_encrypt+0xc0/0xd0 [pcrypt] crypto_aead_encrypt+0x1f/0x30 do_mult_aead_op+0x4e/0xdf [tcrypt] test_mb_aead_speed.constprop.0.cold+0x226/0x564 [tcrypt] do_test+0x28c2/0x4d49 [tcrypt] tcrypt_mod_init+0x55/0x1000 [tcrypt] ... cpumask_weight() in padata_cpu_hash() returns 0 because the mask has no CPUs. The problem is __padata_remove_cpu() checks for valid masks too early and so doesn't mark the instance PADATA_INVALID as expected, which would have made padata_do_parallel() return error before doing the division. Fix by introducing a second padata CPU hotplug state before CPUHP_BRINGUP_CPU so that __padata_remove_cpu() sees the online mask without @cpu. No need for the second argument to padata_replace() since @cpu is now already missing from the online mask. Fixes: 33e54450683c ("padata: Handle empty padata cpumasks") Signed-off-by: Daniel Jordan Cc: Eric Biggers Cc: Herbert Xu Cc: Sebastian Andrzej Siewior Cc: Steffen Klassert Cc: Thomas Gleixner Cc: linux-crypto@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Herbert Xu --- include/linux/cpuhotplug.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/cpuhotplug.h') diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index e51ee772b9f5..def48a583670 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -59,6 +59,7 @@ enum cpuhp_state { CPUHP_IOMMU_INTEL_DEAD, CPUHP_LUSTRE_CFS_DEAD, CPUHP_AP_ARM_CACHE_B15_RAC_DEAD, + CPUHP_PADATA_DEAD, CPUHP_WORKQUEUE_PREP, CPUHP_POWER_NUMA_PREPARE, CPUHP_HRTIMERS_PREPARE, -- cgit v1.2.3-59-g8ed1b