From: "Uladzislau Rezki (Sony)" urezki@gmail.com
[ Upstream commit afd07389d3f4933c7f7817a92fb5e053d59a3182 ]
One of the vmalloc stress test case triggers the kernel BUG():
<snip> [60.562151] ------------[ cut here ]------------ [60.562154] kernel BUG at mm/vmalloc.c:512! [60.562206] invalid opcode: 0000 [#1] PREEMPT SMP PTI [60.562247] CPU: 0 PID: 430 Comm: vmalloc_test/0 Not tainted 4.20.0+ #161 [60.562293] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [60.562351] RIP: 0010:alloc_vmap_area+0x36f/0x390 <snip>
it can happen due to big align request resulting in overflowing of calculated address, i.e. it becomes 0 after ALIGN()'s fixup.
Fix it by checking if calculated address is within vstart/vend range.
Link: http://lkml.kernel.org/r/20190124115648.9433-2-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) urezki@gmail.com Reviewed-by: Andrew Morton akpm@linux-foundation.org Cc: Ingo Molnar mingo@elte.hu Cc: Joel Fernandes joelaf@google.com Cc: Matthew Wilcox willy@infradead.org Cc: Michal Hocko mhocko@suse.com Cc: Oleksiy Avramchenko oleksiy.avramchenko@sonymobile.com Cc: Steven Rostedt rostedt@goodmis.org Cc: Tejun Heo tj@kernel.org Cc: Thomas Garnier thgarnie@google.com Cc: Thomas Gleixner tglx@linutronix.de Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- mm/vmalloc.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 91a789a46b12..a46ec261a44e 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -498,7 +498,11 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, }
found: - if (addr + size > vend) + /* + * Check also calculated address against the vstart, + * because it can be 0 because of big align request. + */ + if (addr + size > vend || addr < vstart) goto overflow;
va->va_start = addr;