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a99f03428f
verify_and_add_patch() allocates memory for a microcode patch and hands
it down to be added to the cache of patches. However, if the cache
already has the latest patch, the newly allocated one needs to be freed
before returning. Do that.
This issue has been found by kmemleak:
unreferenced object 0xffff88010e780b40 (size 32):
comm "bash", pid 860, jiffies 4294690939 (age 29.297s)
backtrace:
kmemleak_alloc
kmem_cache_alloc_trace
load_microcode_amd.isra.0
request_microcode_amd
reload_store
dev_attr_store
sysfs_kf_write
kernfs_fop_write
__vfs_write
vfs_write
SyS_write
do_syscall_64
return_from_SYSCALL_64
0xffffffffffffffff
(gdb) list *0xffffffff81050d60
0xffffffff81050d60 is in load_microcode_amd
(arch/x86/kernel/cpu/microcode/amd.c:616).
which is this:
patch = kzalloc(sizeof(*patch), GFP_KERNEL);
--> if (!patch) {
pr_err("Patch allocation failure.\n");
return -EINVAL;
}
Signed-off-by: Shu Wang <shuwang@redhat.com>
[ Rewrite commit message. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: chuhu@redhat.com
Cc: liwang@redhat.com
Link: http://lkml.kernel.org/r/20170724101228.17326-2-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. 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.