From: Mike Rapoport rppt@linux.ibm.com
mainline inclusion from mainline-v5.1-rc1 commit 5c01a25a210366362a40dc63f550e72688a60c48 category: bugfix bugzilla: 42401 CVE: NA
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Marc Gonzalez reported the following kmemleak crash:
Unable to handle kernel paging request at virtual address ffffffc021e00000 Mem abort info: ESR = 0x96000006 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000006 CM = 0, WnR = 0 swapper pgtable: 4k pages, 39-bit VAs, pgdp = (____ptrval____) [ffffffc021e00000] pgd=000000017e3ba803, pud=000000017e3ba803, pmd=0000000000000000 Internal error: Oops: 96000006 [#1] PREEMPT SMP Modules linked in: CPU: 6 PID: 523 Comm: kmemleak Tainted: G S W 5.0.0-rc1 #13 Hardware name: Qualcomm Technologies, Inc. MSM8998 v1 MTP (DT) pstate: 80000085 (Nzcv daIf -PAN -UAO) pc : scan_block+0x70/0x190 lr : scan_block+0x6c/0x190 Process kmemleak (pid: 523, stack limit = 0x(____ptrval____)) Call trace: scan_block+0x70/0x190 scan_gray_list+0x108/0x1c0 kmemleak_scan+0x33c/0x7c0 kmemleak_scan_thread+0x98/0xf0 kthread+0x11c/0x120 ret_from_fork+0x10/0x1c Code: f9000fb4 d503201f 97ffffd2 35000580 (f9400260)
The crash happens when a no-map area is allocated in early_init_dt_alloc_reserved_memory_arch(). The allocated region is registered with kmemleak, but it is then removed from memblock using memblock_remove() that is not kmemleak-aware.
Replacing memblock_phys_alloc_range() with memblock_find_in_range() makes sure that the allocated memory is not added to kmemleak and then memblock_remove()'ing this memory is safe.
As a bonus, since memblock_find_in_range() ensures the allocation in the specified range, the bounds check can be removed.
[rppt@linux.ibm.com: of: fix parameters order for call to memblock_find_in_range()] Link: http://lkml.kernel.org/r/20190221112619.GC32004@rapoport-lnx Link: http://lkml.kernel.org/r/20190213181921.GB15270@rapoport-lnx Fixes: 3f0c820664483 ("drivers: of: add initialization code for dynamic reserved memory") Signed-off-by: Mike Rapoport rppt@linux.ibm.com Acked-by: Marek Szyprowski m.szyprowski@samsung.com Acked-by: Prateek Patel prpatel@nvidia.com Tested-by: Marc Gonzalez marc.w.gonzalez@free.fr Cc: Rob Herring robh+dt@kernel.org Cc: Frank Rowand frowand.list@gmail.com Cc: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Liu Shixin liushixin2@huawei.com Reviewed-by: Kefeng Wang wangkefeng.wang@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/of/of_reserved_mem.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-)
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c index 166570098cf8..a3a3180b1561 100644 --- a/drivers/of/of_reserved_mem.c +++ b/drivers/of/of_reserved_mem.c @@ -37,22 +37,15 @@ int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size, * panic()s on allocation failure. */ end = !end ? MEMBLOCK_ALLOC_ANYWHERE : end; - base = __memblock_alloc_base(size, align, end); + base = memblock_find_in_range(start, end, size, align); if (!base) return -ENOMEM;
- /* - * Check if the allocated region fits in to start..end window - */ - if (base < start) { - memblock_free(base, size); - return -ENOMEM; - } - *res_base = base; if (nomap) return memblock_remove(base, size); - return 0; + + return memblock_reserve(base, size); } #else int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,