| Message ID | 20211020174406.17889-8-ebiederm@xmission.com |
|---|---|
| State | New |
| Headers | show |
| Series | exit cleanups | expand |
On Wed, Oct 20, 2021 at 12:43:54PM -0500, Eric W. Biederman wrote: > The function setup_tsb_params has exactly one caller tsb_grow. The > function tsb_grow passes in a tsb_bytes value that is between 8192 and > 1048576 inclusive, and is guaranteed to be a power of 2. The function > setup_tsb_params verifies this property with a switch statement and > then prints an error and causes the task to exit if this is not true. > > In practice that print statement can never be reached because tsb_grow > never passes in a bad tsb_size. So if tsb_size ever gets a bad value > that is a kernel bug. > > So replace the do_exit which is effectively an open coded version of > BUG() with an actuall call to BUG(). Making it clearer that this > is a case that can never, and should never happen. > > Cc: David Miller <davem@davemloft.net> > Cc: sparclinux@vger.kernel.org > Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> > --- > arch/sparc/mm/tsb.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c > index 0dce4b7ff73e..912205787161 100644 > --- a/arch/sparc/mm/tsb.c > +++ b/arch/sparc/mm/tsb.c > @@ -266,7 +266,7 @@ static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_idx, unsign > default: > printk(KERN_ERR "TSB[%s:%d]: Impossible TSB size %lu, killing process.\n", > current->comm, current->pid, tsb_bytes); > - do_exit(SIGSEGV); > + BUG(); > } > tte |= pte_sz_bits(page_sz); Given the other uses of BUG() here, this seems okay. Reviewed-by: Kees Cook <keescook@chromium.org>
diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c index 0dce4b7ff73e..912205787161 100644 --- a/arch/sparc/mm/tsb.c +++ b/arch/sparc/mm/tsb.c @@ -266,7 +266,7 @@ static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_idx, unsign default: printk(KERN_ERR "TSB[%s:%d]: Impossible TSB size %lu, killing process.\n", current->comm, current->pid, tsb_bytes); - do_exit(SIGSEGV); + BUG(); } tte |= pte_sz_bits(page_sz);
The function setup_tsb_params has exactly one caller tsb_grow. The function tsb_grow passes in a tsb_bytes value that is between 8192 and 1048576 inclusive, and is guaranteed to be a power of 2. The function setup_tsb_params verifies this property with a switch statement and then prints an error and causes the task to exit if this is not true. In practice that print statement can never be reached because tsb_grow never passes in a bad tsb_size. So if tsb_size ever gets a bad value that is a kernel bug. So replace the do_exit which is effectively an open coded version of BUG() with an actuall call to BUG(). Making it clearer that this is a case that can never, and should never happen. Cc: David Miller <davem@davemloft.net> Cc: sparclinux@vger.kernel.org Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> --- arch/sparc/mm/tsb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)