| Message ID | 1436227867-24828-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c index 9c2ba1c..df0c66c 100644 --- a/drivers/base/cacheinfo.c +++ b/drivers/base/cacheinfo.c @@ -179,7 +179,7 @@ static int detect_cache_attributes(unsigned int cpu) { int ret; - if (init_cache_level(cpu)) + if (init_cache_level(cpu) || !cache_leaves(cpu)) return -ENOENT; per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
This is a note to let you know that I have just added a patch titled drivers/base: cacheinfo: handle absence of caches to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue This patch is scheduled to be released in version 3.19.8-ckt3. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.19.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From b8cc91d0a874cf39cc858054b711a0e989b200bf Mon Sep 17 00:00:00 2001 From: Sudeep Holla <sudeep.holla@arm.com> Date: Wed, 27 May 2015 11:26:13 +0100 Subject: drivers/base: cacheinfo: handle absence of caches commit 3370e13aa463adb84488ebf0e599e3dc0024315b upstream. On some simulators like GEM5, caches may not be simulated. In those cases, the cache levels and leaves will be zero and will result in following exception: Unable to handle kernel NULL pointer dereference at virtual address 0040 pgd = ffffffc0008fa000 [00000040] *pgd=00000009f6807003, *pud=00000009f6807003, *pmd=00000009f6808003, *pte=006000002c010707 Internal error: Oops: 96000005 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.1.0-rc5 #198 task: ffffffc9768a0000 ti: ffffffc9768a8000 task.ti: ffffffc9768a8000 PC is at detect_cache_attributes+0x98/0x2c8 LR is at detect_cache_attributes+0x88/0x2c8 kcalloc(0) returns a special value ZERO_SIZE_PTR which is non-NULL value but results in fault only on any attempt to dereferencing it. So checking for the non-NULL pointer will not suffice. This patch checks for non-zero cache leaf nodes and returns error if there are no cache leaves in detect_cache_attributes. Cc: Will Deacon <will.deacon@arm.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reported-by: William Wang <william.wang@arm.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/base/cacheinfo.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 1.9.1