On Sep 6, 2023, at 3:14 PM, Lorenzo Stoakes lstoakes@gmail.com wrote:
On Wed, 6 Sept 2023 at 16:09, Andrew Morton akpm@linux-foundation.org wrote:
The quilt patch titled Subject: mm/vmalloc: add a safer version of find_vm_area() for debug has been removed from the -mm tree. Its filename was mm-vmalloc-add-a-safer-version-of-find_vm_area-for-debug.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Hmm, I had outstanding review on this :/ I guess I will have to send a follow up patch to address those concerns...
That works me because we also had some disagreements on some of the suggestions!
Looking forward to your patch and discussing it!
Cheers,
- Joel
From: "Joel Fernandes (Google)" joel@joelfernandes.org Subject: mm/vmalloc: add a safer version of find_vm_area() for debug Date: Mon, 4 Sep 2023 18:08:04 +0000
It is unsafe to dump vmalloc area information when trying to do so from some contexts. Add a safer trylock version of the same function to do a best-effort VMA finding and use it from vmalloc_dump_obj().
[applied test robot feedback on unused function fix.] [applied Uladzislau feedback on locking.] Link: https://lkml.kernel.org/r/20230904180806.1002832-1-joel@joelfernandes.org Fixes: 98f180837a89 ("mm: Make mem_dump_obj() handle vmalloc() memory") Signed-off-by: Joel Fernandes (Google) joel@joelfernandes.org Reviewed-by: Uladzislau Rezki (Sony) urezki@gmail.com Reported-by: Zhen Lei thunder.leizhen@huaweicloud.com Cc: Paul E. McKenney paulmck@kernel.org Cc: Zqiang qiang.zhang1211@gmail.com Cc: stable@vger.kernel.org Cc: Matthew Wilcox (Oracle) willy@infradead.org Signed-off-by: Andrew Morton akpm@linux-foundation.org
mm/vmalloc.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-)
--- a/mm/vmalloc.c~mm-vmalloc-add-a-safer-version-of-find_vm_area-for-debug +++ a/mm/vmalloc.c @@ -4278,14 +4278,32 @@ void pcpu_free_vm_areas(struct vm_struct #ifdef CONFIG_PRINTK bool vmalloc_dump_obj(void *object) {
struct vm_struct *vm; void *objp = (void *)PAGE_ALIGN((unsigned long)object);
const void *caller;struct vm_struct *vm;struct vmap_area *va;unsigned long addr;unsigned int nr_pages;if (!spin_trylock(&vmap_area_lock))return false;va = __find_vmap_area((unsigned long)objp, &vmap_area_root);if (!va) {spin_unlock(&vmap_area_lock);return false;}
vm = find_vm_area(objp);if (!vm)
vm = va->vm;if (!vm) {spin_unlock(&vmap_area_lock); return false;}addr = (unsigned long)vm->addr;caller = vm->caller;nr_pages = vm->nr_pages;spin_unlock(&vmap_area_lock); pr_cont(" %u-page vmalloc region starting at %#lx allocated at %pS\n",
vm->nr_pages, (unsigned long)vm->addr, vm->caller);
nr_pages, addr, caller); return true;} #endif _
Patches currently in -mm which might be from joel@joelfernandes.org are
-- Lorenzo Stoakes https://ljs.io