Hi,

On Thu, Feb 07, 2019 at 04:32:13PM +0000, Sasha Levin wrote:

Hi,

[This is an automated email]

This commit has been processed because it contains a "Fixes:" tag, fixing commit: 3f0c82066448 drivers: of: add initialization code for dynamic reserved memory.

The bot has tested the following trees: v4.20.6, v4.19.19, v4.14.97, v4.9.154, v4.4.172, v3.18.133.

...

How should we proceed with this patch?

Below is the backport of the patch to 4.19.19 and below. I've build-tested for 4.19 and verified it applies cleanly to the older versions.

From 2052bf06134fd8feae3e621acea6421f916bbbae Mon Sep 17 00:00:00 2001

From: Mike Rapoport rppt@linux.ibm.com Date: Mon, 4 Feb 2019 15:37:21 +0100 Subject: [PATCH] of: fix kmemleak crash caused by imbalance in early memory reservation

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 sp : ffffff8012e8bd20 x29: ffffff8012e8bd20 x28: ffffffc0fdbaf018 x27: ffffffc022000000 x26: 0000000000000080 x25: ffffff8011aadf70 x24: ffffffc0f8cc8000 x23: ffffff8010dc8000 x22: ffffff8010dc8830 x21: ffffffc021e00ff9 x20: ffffffc0f8cc8050 x19: ffffffc021e00000 x18: 0000000000002409 x17: 0000000000000200 x16: 0000000000000000 x15: ffffff8010e14dd8 x14: 0000000000002406 x13: 000000004c4dd0c6 x12: ffffffc0f77dad58 x11: 0000000000000001 x10: ffffff8010d9e688 x9 : ffffff8010d9f000 x8 : ffffff8010d9e688 x7 : 0000000000000002 x6 : 0000000000000000 x5 : ffffff8011511c20 x4 : 00000000000026d1 x3 : ffffff8010e14d88 x2 : 5b36396f4e7d4000 x1 : 0000000000208040 x0 : 0000000000000000 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) ---[ end trace 176d6ed9d86a0c33 ]--- note: kmemleak[523] exited with preempt_count 2

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_alloc_base() 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.

Cc: stable@vger.kernel.org # 3.15+ Fixes: 3f0c820664483 ("drivers: of: add initialization code for dynamic reserved memory") Acked-by: Marek Szyprowski m.szyprowski@samsung.com Acked-by: Prateek Patel prpatel@nvidia.com Tested-by: Marc Gonzalez marc.w.gonzalez@free.fr Signed-off-by: Mike Rapoport rppt@linux.ibm.com --- drivers/of/of_reserved_mem.c | 18 +++++------------- 1 file changed, 5 insertions(+), 13 deletions(-)

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c index 895c83e..240763b 100644 --- a/drivers/of/of_reserved_mem.c +++ b/drivers/of/of_reserved_mem.c @@ -32,26 +32,18 @@ int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size, phys_addr_t *res_base) { phys_addr_t base; - /* - * We use __memblock_alloc_base() because memblock_alloc_base() - * panic()s on allocation failure. - */ + end = !end ? MEMBLOCK_ALLOC_ANYWHERE : end; - base = __memblock_alloc_base(size, align, end); + base = memblock_find_in_range(size, align, start, end); 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); + else + return memblock_reserve(base, size); + return 0; } #else