Daniel Jordan
1538674cee
[ Upstream commitec9c7d1933] Exercising CPU hotplug on a 5.2 kernel with recent padata fixes from cryptodev-2.6.git in an 8-CPU kvm guest... # modprobe tcrypt alg="pcrypt(rfc4106(gcm(aes)))" type=3 # echo 0 > /sys/devices/system/cpu/cpu1/online # echo c > /sys/kernel/pcrypt/pencrypt/parallel_cpumask # modprobe tcrypt mode=215 ...caused the following crash: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 2 PID: 134 Comm: kworker/2:2 Not tainted 5.2.0-padata-base+ #7 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-<snip> Workqueue: pencrypt padata_parallel_worker RIP: 0010:padata_reorder+0xcb/0x180 ... Call Trace: padata_do_serial+0x57/0x60 pcrypt_aead_enc+0x3a/0x50 [pcrypt] padata_parallel_worker+0x9b/0xe0 process_one_work+0x1b5/0x3f0 worker_thread+0x4a/0x3c0 ... In padata_alloc_pd, pd->cpu is set using the user-supplied cpumask instead of the effective cpumask, and in this case cpumask_first picked an offline CPU. The offline CPU's reorder->list.next is NULL in padata_reorder because the list wasn't initialized in padata_init_pqueues, which only operates on CPUs in the effective mask. Fix by using the effective mask in padata_alloc_pd. Fixes:6fc4dbcf02("padata: Replace delayed timer with immediate workqueue in padata_reorder") Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: linux-crypto@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.