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| author | Sudeep Holla <sudeep.holla@arm.com> | 2015-05-27 11:26:13 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-06-01 10:34:24 +0900 |
| commit | 3370e13aa463adb84488ebf0e599e3dc0024315b (patch) | |
| tree | 23b6ab2c26ca2ade363b6f9a37803defbded11c2 /drivers/base | |
| parent | 194ec9368c0dbc421acdb2620d4dfb3cc3d022ff (diff) | |
| download | linux-3370e13aa463adb84488ebf0e599e3dc0024315b.tar.gz | |
drivers/base: cacheinfo: handle absence of caches
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: <stable@vger.kernel.org> # 3.19.x 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>
Diffstat (limited to 'drivers/base')
| -rw-r--r-- | drivers/base/cacheinfo.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c index 9c2ba1c97c42..df0c66cb7ad3 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), |