| Message ID | 20190905232951.GA28779@LGEARND20B15 (mailing list archive) |
|---|---|
| State | Deferred, archived |
| Headers | show |
| Series | x86/platform/uv: move kmalloc() NULL check routine | expand |
On Fri, Sep 06, 2019 at 08:29:51AM +0900, Austin Kim wrote: > The result of kmalloc should have been checked ahead of below statement: > pqp = (struct bau_pq_entry *)vp; > > Move BUG_ON(!vp) before above statement. > > Signed-off-by: Austin Kim <austindh.kim@gmail.com> > --- > arch/x86/platform/uv/tlb_uv.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c > index 20c389a..5f0a96bf 100644 > --- a/arch/x86/platform/uv/tlb_uv.c > +++ b/arch/x86/platform/uv/tlb_uv.c > @@ -1804,9 +1804,9 @@ static void pq_init(int node, int pnode) > > plsize = (DEST_Q_SIZE + 1) * sizeof(struct bau_pq_entry); > vp = kmalloc_node(plsize, GFP_KERNEL, node); > - pqp = (struct bau_pq_entry *)vp; > - BUG_ON(!pqp); > + BUG_ON(!vp); Ick! Don't crash the whole machine if you are out of memory, that's a totally lazy and broken driver. Fix this up properly please. But the original code is just fine (from a this is doing what I want it to do point of view), I don't see the need to change anything here, you did not modify any logic at all. thanks, greg k-h
On Fri, Sep 06, 2019 at 11:32:52AM +0200, Greg KH wrote: > On Fri, Sep 06, 2019 at 08:29:51AM +0900, Austin Kim wrote: > > The result of kmalloc should have been checked ahead of below statement: > > pqp = (struct bau_pq_entry *)vp; > > > > Move BUG_ON(!vp) before above statement. > > > > Signed-off-by: Austin Kim <austindh.kim@gmail.com> > > --- > > arch/x86/platform/uv/tlb_uv.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c > > index 20c389a..5f0a96bf 100644 > > --- a/arch/x86/platform/uv/tlb_uv.c > > +++ b/arch/x86/platform/uv/tlb_uv.c > > @@ -1804,9 +1804,9 @@ static void pq_init(int node, int pnode) > > > > plsize = (DEST_Q_SIZE + 1) * sizeof(struct bau_pq_entry); > > vp = kmalloc_node(plsize, GFP_KERNEL, node); > > - pqp = (struct bau_pq_entry *)vp; > > - BUG_ON(!pqp); > > + BUG_ON(!vp); > > Ick! Don't crash the whole machine if you are out of memory, that's a > totally lazy and broken driver. Fix this up properly please. This is boot time init; if memory allocation fails, we're in trouble, no way forward no way back. It is not uncommon to have BUG_ON() for alloc failing during boot. > But the original code is just fine (from a this is doing what I want it > to do point of view), I don't see the need to change anything here, you > did not modify any logic at all. Agreed, the patch seems entirely pointless.
On Fri, Sep 06, 2019 at 12:43:41PM +0200, Peter Zijlstra wrote: > On Fri, Sep 06, 2019 at 11:32:52AM +0200, Greg KH wrote: > > On Fri, Sep 06, 2019 at 08:29:51AM +0900, Austin Kim wrote: > > > The result of kmalloc should have been checked ahead of below statement: > > > pqp = (struct bau_pq_entry *)vp; > > > > > > Move BUG_ON(!vp) before above statement. > > > > > > Signed-off-by: Austin Kim <austindh.kim@gmail.com> > > > --- > > > arch/x86/platform/uv/tlb_uv.c | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c > > > index 20c389a..5f0a96bf 100644 > > > --- a/arch/x86/platform/uv/tlb_uv.c > > > +++ b/arch/x86/platform/uv/tlb_uv.c > > > @@ -1804,9 +1804,9 @@ static void pq_init(int node, int pnode) > > > > > > plsize = (DEST_Q_SIZE + 1) * sizeof(struct bau_pq_entry); > > > vp = kmalloc_node(plsize, GFP_KERNEL, node); > > > - pqp = (struct bau_pq_entry *)vp; > > > - BUG_ON(!pqp); > > > + BUG_ON(!vp); > > > > Ick! Don't crash the whole machine if you are out of memory, that's a > > totally lazy and broken driver. Fix this up properly please. > > This is boot time init; if memory allocation fails, we're in trouble, no > way forward no way back. > > It is not uncommon to have BUG_ON() for alloc failing during boot. Hey, how come you get to get away with this here, and in the tty layer I had to do all sorts of foolish things just for the same "impossible" thing because syzbot found a way to emulate such lunacy? Just you wait until the fuzzers get ahold of this code... :) greg k-h
diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c index 20c389a..5f0a96bf 100644 --- a/arch/x86/platform/uv/tlb_uv.c +++ b/arch/x86/platform/uv/tlb_uv.c @@ -1804,9 +1804,9 @@ static void pq_init(int node, int pnode) plsize = (DEST_Q_SIZE + 1) * sizeof(struct bau_pq_entry); vp = kmalloc_node(plsize, GFP_KERNEL, node); - pqp = (struct bau_pq_entry *)vp; - BUG_ON(!pqp); + BUG_ON(!vp); + pqp = (struct bau_pq_entry *)vp; cp = (char *)pqp + 31; pqp = (struct bau_pq_entry *)(((unsigned long)cp >> 5) << 5);
The result of kmalloc should have been checked ahead of below statement: pqp = (struct bau_pq_entry *)vp; Move BUG_ON(!vp) before above statement. Signed-off-by: Austin Kim <austindh.kim@gmail.com> --- arch/x86/platform/uv/tlb_uv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)