diff options
| author | Joel Fernandes (Google) <joel@joelfernandes.org> | 2023-09-04 18:08:04 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-09-05 10:13:45 -0700 |
| commit | 0818e739b5c061b0251c30152380600fb9b84c0c (patch) | |
| tree | e46a53aed8e55375d0fe8b04491a89966b57b765 /mm | |
| parent | 7f33105cdd59a99d068d3d147723a865d10e2260 (diff) | |
| download | lwn-0818e739b5c061b0251c30152380600fb9b84c0c.tar.gz lwn-0818e739b5c061b0251c30152380600fb9b84c0c.zip | |
mm/vmalloc: add a safer version of find_vm_area() for debug
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>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/vmalloc.c | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 228a4a5312f2..ef8599d394fd 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -4278,14 +4278,32 @@ void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms) #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; - vm = find_vm_area(objp); - if (!vm) + 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 = 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 |