Messages in this thread Patch in this message | | | Subject | Re: [PATCH 2/2] mm: vmalloc: Pass proper vm_start into debugobjects | From | Chintan Pandya <> | Date | Mon, 16 Apr 2018 17:39:07 +0530 |
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On 4/13/2018 5:31 PM, Anshuman Khandual wrote: > On 04/13/2018 05:03 PM, Chintan Pandya wrote: >> Client can call vunmap with some intermediate 'addr' >> which may not be the start of the VM area. Entire >> unmap code works with vm->vm_start which is proper >> but debug object API is called with 'addr'. This >> could be a problem within debug objects. >> >> Pass proper start address into debug object API. >> >> Signed-off-by: Chintan Pandya <cpandya@codeaurora.org> >> --- >> mm/vmalloc.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/mm/vmalloc.c b/mm/vmalloc.c >> index 9ff21a1..28034c55 100644 >> --- a/mm/vmalloc.c >> +++ b/mm/vmalloc.c >> @@ -1526,8 +1526,8 @@ static void __vunmap(const void *addr, int deallocate_pages) >> return; >> } >> >> - debug_check_no_locks_freed(addr, get_vm_area_size(area)); >> - debug_check_no_obj_freed(addr, get_vm_area_size(area)); >> + debug_check_no_locks_freed(area->addr, get_vm_area_size(area)); >> + debug_check_no_obj_freed(area->addr, get_vm_area_size(area)); > > This kind of makes sense to me but I am not sure. We also have another > instance of this inside the function vm_unmap_ram() where we call for Right, I missed it. I plan to add below stub in v2.
--- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1124,15 +1124,15 @@ void vm_unmap_ram(const void *mem, unsigned int count) BUG_ON(addr > VMALLOC_END); BUG_ON(!PAGE_ALIGNED(addr));
- debug_check_no_locks_freed(mem, size); - if (likely(count <= VMAP_MAX_ALLOC)) { + debug_check_no_locks_freed(mem, size); vb_free(mem, size); return; }
va = find_vmap_area(addr); BUG_ON(!va); + debug_check_no_locks_freed(va->va_start, (va->va_end - va->va_start)); free_unmap_vmap_area(va); } EXPORT_SYMBOL(vm_unmap_ram);
> debug on locks without even finding the vmap_area first. But it is true > that in both these functions the vmap_area gets freed eventually. Hence > the entire mapping [va->va_start --> va->va_end] gets unmapped. Sounds > like these debug functions should have the entire range as argument. > But I am not sure and will seek Michal's input on this. >
Chintan -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
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