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8a04d2fc70
Currently if ipcomp_alloc_scratches() fails to allocate memory
ipcomp_scratches holds obsolete address. So when we try to free the
percpu scratches using ipcomp_free_scratches() it tries to vfree non
existent vm area. Described below:
static void * __percpu *ipcomp_alloc_scratches(void)
{
...
scratches = alloc_percpu(void *);
if (!scratches)
return NULL;
ipcomp_scratches does not know about this allocation failure.
Therefore holding the old obsolete address.
...
}
So when we free,
static void ipcomp_free_scratches(void)
{
...
scratches = ipcomp_scratches;
Assigning obsolete address from ipcomp_scratches
if (!scratches)
return;
for_each_possible_cpu(i)
vfree(*per_cpu_ptr(scratches, i));
Trying to free non existent page, causing warning: trying to vfree
existent vm area.
...
}
Fix this breakage by updating ipcomp_scrtches with NULL when scratches
is freed
Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
Reported-by: syzbot+5ec9bb042ddfe9644773@syzkaller.appspotmail.com
Tested-by: syzbot+5ec9bb042ddfe9644773@syzkaller.appspotmail.com
Signed-off-by: Khalid Masum <khalid.masum.92@gmail.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
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.
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.