Messages in this thread Patch in this message | | | Subject | Re: [PATCH] of: reserved_mem: disable kmemleak scan on removed memory blocks | From | Prateek Patel <> | Date | Tue, 22 Jan 2019 14:16:06 +0530 |
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On 11/10/2018 2:58 AM, Rob Herring wrote: > On Fri, Nov 9, 2018 at 1:09 AM Prateek Patel <prpatel@nvidia.com> wrote: >> From: Sri Krishna chowdary <schowdary@nvidia.com> >> >> Memory reserved with "nomap" DT property in of_reserved_mem.c >> removes the memory block. The removed memory blocks don't have >> VA to PA mapping created in kernel page table. Kmemleak scan on >> removed memory blocks is causing page faults and leading to >> kernel panic. So, Disable kmemleak scan on the removed memory >> blocks. >> >> Following is the observed crash log: >> [ 154.846370] Unable to handle kernel paging request at virtual address ffffffc070a00000 >> <1>[ 154.846576] Mem abort info: >> <1>[ 154.846635] Exception class = DABT (current EL), IL = 32 bits >> <1>[ 154.846737] SET = 0, FnV = 0 >> <1>[ 154.846796] EA = 0, S1PTW = 0 >> <1>[ 154.846859] Data abort info: >> <1>[ 154.846913] ISV = 0, ISS = 0x00000006 >> <1>[ 154.846983] CM = 0, WnR = 0 >> <1>[ 154.847053] swapper pgtable: 4k pages, 39-bit VAs, pgd = ffffff8009df7000 >> <1>[ 154.847228] [ffffffc070a00000] *pgd=000000087fff5803, *pud=000000087fff5803, *pmd=0000000000000000 >> <0>[ 154.847408] Internal error: Oops: 96000006 [#1] PREEMPT SMP >> <4>[ 154.847511] Modules linked in: nvs_led_test nvs_bmi160 nvs_cm3218 nvs_bh1730fvc nvi_bmpX80 nvi_ak89xx nvi_mpu cdc_acm uas lr388k7_ts imx268 imx318 imx204 imx274 imx185 lc898212 ov23850 ov10823 ov9281 ov5693 tc358840 pca9570 nvs snd_soc_tegra_machine_driver_mobile lp855x_bl spidev input_cfboost pwm_tegra tegra_cryptodev tegra_se_nvhost tegra_se_elp tegra_se ghash_ce sha2_ce sha1_ce aes_ce_ccm cryptd nvgpu cpufreq_userspace snd_soc_tegra186_alt_dspk snd_soc_tegra186_alt_asrc snd_soc_tegra186_alt_arad snd_soc_tegra210_alt_ope snd_soc_tegra210_alt_mvc snd_soc_tegra210_alt_dmic snd_soc_tegra210_alt_amx snd_soc_tegra210_alt_adx snd_soc_tegra210_alt_afc snd_soc_tegra210_alt_mixer snd_soc_tegra210_alt_i2s snd_soc_tegra210_alt_sfc snd_soc_tegra210_alt_adsp snd_soc_tegra210_alt_admaif snd_soc_tegra210_alt_xbar >> <4>[ 154.882606] snd_soc_tegra_alt_utils snd_hda_tegra >> <4>[ 154.888133] CPU: 2 PID: 8079 Comm: sh Not tainted 4.14.53-tegra-05132-g9c33465 #2 >> <4>[ 154.895983] Hardware name: e3360_1099 (DT) >> <4>[ 154.900447] task: ffffffc7d62dda00 task.stack: ffffff800e2b0000 >> <4>[ 154.906502] PC is at scan_block+0x7c/0x148 >> <4>[ 154.911234] LR is at scan_block+0x78/0x148 >> <4>[ 154.915689] pc : [<ffffff8008271724>] lr : [<ffffff8008271720>] pstate: 804000c9 >> <4>[ 154.923290] sp : ffffff800e2b3b80 >> <4>[ 154.927228] x29: ffffff800e2b3b80 x28: ffffffc7d62dda00 >> <4>[ 154.932999] x27: ffffff8009aaa000 x26: ffffffc070c00000 >> <4>[ 154.938769] x25: 00000000000000c0 x24: ffffff8009d90608 >> <4>[ 154.944287] x23: ffffffc7dc6c6000 x22: ffffff8009d90000 >> <4>[ 154.950320] x21: ffffff8009aeb320 x20: ffffffc070a00ff9 >> <4>[ 154.955919] x19: ffffffc070a00000 x18: 00000000bec4c3f2 >> <4>[ 154.961438] x17: 0000002224777924 x16: ffffff80080bb0e0 >> <4>[ 154.967124] x15: 0000000000000000 x14: 0000000000000f75 >> <4>[ 154.973069] x13: 000fffffffffffff x12: ffffffbf1e9f4240 >> <4>[ 154.978670] x11: 0000000000000040 x10: 0000000000000ad0 >> <4>[ 154.984107] x9 : ffffff800e2b3ab0 x8 : ffffffc7d62de530 >> <4>[ 154.989958] x7 : 0000000780000000 x6 : 0000000000000018 >> <4>[ 154.995645] x5 : 0000000000000000 x4 : 0000000000000000 >> <4>[ 155.001245] x3 : ffffff8009aaa000 x2 : 00000047f6712000 >> <4>[ 155.006846] x1 : ffffffc7d1ae6900 x0 : 0000000000000000 >> >> Signed-off-by: Sri Krishna chowdary <schowdary@nvidia.com> >> Signed-off-by: Prateek <prpatel@nvidia.com> >> --- >> drivers/of/of_reserved_mem.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c >> index 1977ee0..ac8f377 100644 >> --- a/drivers/of/of_reserved_mem.c >> +++ b/drivers/of/of_reserved_mem.c >> @@ -21,6 +21,7 @@ >> #include <linux/sort.h> >> #include <linux/slab.h> >> #include <linux/memblock.h> >> +#include <linux/kmemleak.h> >> >> #define MAX_RESERVED_REGIONS 32 >> static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS]; >> @@ -50,8 +51,10 @@ int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size, >> } >> >> *res_base = base; >> - if (nomap) >> + if (nomap) { >> + kmemleak_no_scan(__va(base)); >> return memblock_remove(base, size); > I'm curious how I can't find any other similar example in the kernel. > Please Cc some kmemleak folks. > > Perhaps we should be using memblock_mark_nomap() for nomap areas? > > Rob
Sorry for this late reply.
Yes, memblock_mark_nomap() can be used here but if I understand correctly, memblock_mark_nomap() is used to indicate marked parts of memory should not be covered by the kernel direct mapping and memblock_remove() here is doing that by removing a given memory from the "memblock.memory" list to prevent the memory from CPU accessing by the linear address. I am not 100% sure what will be the side effects of using memblock_mark_nomap(). Adding folks to help me here on MEMBLOCK_NOMAP and kmemleak.
I checked and verified with following and I didn't find any errors on my local setup:
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c index 1977ee0..f77cde0 100644 --- a/drivers/of/of_reserved_mem.c +++ b/drivers/of/of_reserved_mem.c @@ -50,8 +50,10 @@ int __init __weak early_init_dt_alloc_reserved_memory_arch(phys_addr_t size, }
*res_base = base; - if (nomap) - return memblock_remove(base, size); + if (nomap) { + kmemleak_no_scan(__va(base)); + return memblock_mark_nomap(base, size); + } return 0; }
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