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Message-ID: <5e5be6bc-5fc1-5def-d1b8-dc2fa4bbc93e@nvidia.com>
Date: Wed, 23 Jan 2019 12:35:01 +0530
From: Prateek Patel <prpatel@...dia.com>
To: Mike Rapoport <rppt@...ux.ibm.com>,
Marc Gonzalez <marc.w.gonzalez@...e.fr>
CC: Rob Herring <robh+dt@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
Sachin Nikam <snikam@...dia.com>,
John Hubbard <jhubbard@...dia.com>,
Ralph Campbell <rcampbell@...dia.com>,
Robin Murphy <robin.murphy@....com>,
Frank Rowand <frowand.list@...il.com>,
Marek Szyprowski <m.szyprowski@...sung.com>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Mark Rutland <mark.rutland@....com>,
Arnd Bergmann <arnd@...db.de>,
Ard Biesheuvel <ard.biesheuvel@...aro.org>,
Oscar Salvador <osalvador@...e.de>,
Wei Yang <richard.weiyang@...il.com>,
Michal Hocko <mhocko@...e.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Qian Cai <cai@....pw>, LKML <linux-kernel@...r.kernel.org>,
<vdumpa@...dia.com>, <praithatha@...dia.com>
Subject: Re: kmemleak panic
On 1/23/2019 11:24 AM, Mike Rapoport wrote:
> On Tue, Jan 22, 2019 at 03:12:54PM +0100, Marc Gonzalez wrote:
>> On 22/01/2019 15:02, Marc Gonzalez wrote:
>>
>>> On 21/01/2019 18:42, Mike Rapoport wrote:
>>>
>>>> If I understood correctly, the trouble comes from no-map range allocated in
>>>> early_init_dt_alloc_reserved_memory_arch().
>>>>
>>>> There's indeed imbalance, because memblock_alloc() does kmemleak_alloc(), but
>>>> memblock_remove() does not do kmemleak_free().
>>>>
>>>> I think the best way is to replace __memblock_alloc_base() with
>>>> memblock_find_in_range(), e.g something like:
>>>>
>>>>
>>>> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
>>>> index 1977ee0adcb1..6807a1cffe55 100644
>>>> --- a/drivers/of/of_reserved_mem.c
>>>> +++ b/drivers/of/of_reserved_mem.c
>>>> @@ -37,21 +37,16 @@ int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
>>>> */
>>>> end = !end ? MEMBLOCK_ALLOC_ANYWHERE : end;
>>>> align = !align ? SMP_CACHE_BYTES : align;
>>>> - 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;
>>>> }
>>>>
>>> Your patch solves the issue. \o/
> Great :)
>
>> [ Add nvidia devs, but drop schowdary@...dia.com ]
>>
> Resending it as a formal patch now, I took a liberty to add your Tested-by.
>
> From a847ca684db29a3c09e4dd2a8a008b35cf36e52f Mon Sep 17 00:00:00 2001
> From: Mike Rapoport <rppt@...ux.ibm.com>
> Date: Wed, 23 Jan 2019 07:38:50 +0200
> 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.
>
> Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>
> Tested-by: Marc Gonzalez <marc.w.gonzalez@...e.fr>
> ---
> drivers/of/of_reserved_mem.c | 13 ++++---------
> 1 file changed, 4 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
> index 1977ee0adcb1..6807a1cffe55 100644
> --- a/drivers/of/of_reserved_mem.c
> +++ b/drivers/of/of_reserved_mem.c
> @@ -37,21 +37,16 @@ int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
> */
> end = !end ? MEMBLOCK_ALLOC_ANYWHERE : end;
> align = !align ? SMP_CACHE_BYTES : align;
> - 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;
> }
>
Thanks Mike for the patch. With this, skipping kmemleak scan:
https://patchwork.ozlabs.org/patch/995367/ is not required.
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