Messages in this thread | | | Subject | Re: [PATCH v3 3/3] powerpc/32: Add KASAN support | From | Christophe Leroy <> | Date | Mon, 21 Jan 2019 09:37:35 +0100 |
| |
Le 21/01/2019 à 09:30, Dmitry Vyukov a écrit : > On Mon, Jan 21, 2019 at 8:17 AM Christophe Leroy > <christophe.leroy@c-s.fr> wrote: >> >> >> >> Le 15/01/2019 à 18:23, Andrey Ryabinin a écrit : >>> >>> >>> On 1/12/19 2:16 PM, Christophe Leroy wrote: >>> >>>> +KASAN_SANITIZE_early_32.o := n >>>> +KASAN_SANITIZE_cputable.o := n >>>> +KASAN_SANITIZE_prom_init.o := n >>>> + >>> >>> Usually it's also good idea to disable branch profiling - define DISABLE_BRANCH_PROFILING >>> either in top of these files or via Makefile. Branch profiling redefines if() statement and calls >>> instrumented ftrace_likely_update in every if(). >>> >>> >>> >>>> diff --git a/arch/powerpc/mm/kasan_init.c b/arch/powerpc/mm/kasan_init.c >>>> new file mode 100644 >>>> index 000000000000..3edc9c2d2f3e >>> >>>> +void __init kasan_init(void) >>>> +{ >>>> + struct memblock_region *reg; >>>> + >>>> + for_each_memblock(memory, reg) >>>> + kasan_init_region(reg); >>>> + >>>> + pr_info("KASAN init done\n"); >>> >>> Without "init_task.kasan_depth = 0;" kasan will not repot bugs. >>> >>> There is test_kasan module. Make sure that it produce reports. >>> >> >> Thanks for the review. >> >> Now I get the following very early in boot, what does that mean ? > > This looks like an instrumented memset call before kasan shadow is > mapped, or kasan shadow is not zeros. Does this happen before or after > mapping of kasan_early_shadow_page?
This is after the mapping of kasan_early_shadow_page.
> This version seems to miss what x86 code has to clear the early shadow: > > /* > * kasan_early_shadow_page has been used as early shadow memory, thus > * it may contain some garbage. Now we can clear and write protect it, > * since after the TLB flush no one should write to it. > */ > memset(kasan_early_shadow_page, 0, PAGE_SIZE);
In the early part, kasan_early_shadow_page is mapped read-only so I assumed this reset of its content was unneccessary.
I'll try with it.
Christophe
> > >> [ 0.000000] KASAN init done >> [ 0.000000] >> ================================================================== >> [ 0.000000] BUG: KASAN: unknown-crash in memblock_alloc_try_nid+0xd8/0xf0 >> [ 0.000000] Write of size 68 at addr c7ff5a90 by task swapper/0 >> [ 0.000000] >> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted >> 5.0.0-rc2-s3k-dev-00559-g88aa407c4bce #772 >> [ 0.000000] Call Trace: >> [ 0.000000] [c094ded0] [c016c7e4] >> print_address_description+0x1a0/0x2b8 (unreliable) >> [ 0.000000] [c094df00] [c016caa0] kasan_report+0xe4/0x168 >> [ 0.000000] [c094df40] [c016b464] memset+0x2c/0x4c >> [ 0.000000] [c094df60] [c08731f0] memblock_alloc_try_nid+0xd8/0xf0 >> [ 0.000000] [c094df90] [c0861f20] mmu_context_init+0x58/0xa0 >> [ 0.000000] [c094dfb0] [c085ca70] start_kernel+0x54/0x400 >> [ 0.000000] [c094dff0] [c0002258] start_here+0x44/0x9c >> [ 0.000000] >> [ 0.000000] >> [ 0.000000] Memory state around the buggy address: >> [ 0.000000] c7ff5980: e2 a1 87 81 bd d4 a5 b5 f8 8d 89 e7 72 bc 20 24 >> [ 0.000000] c7ff5a00: e7 b9 c1 c7 17 e9 b4 bd a4 d0 e7 a0 11 15 a5 b5 >> [ 0.000000] >c7ff5a80: b5 e1 83 a5 2d 65 31 3f f3 e5 a7 ef 34 b5 69 b5 >> [ 0.000000] ^ >> [ 0.000000] c7ff5b00: 21 a5 c1 c1 b4 bf 2d e5 e5 c3 f5 91 e3 b8 a1 34 >> [ 0.000000] c7ff5b80: ad ef 23 87 3d a6 ad b5 c3 c3 80 b7 ac b1 1f 37 >> [ 0.000000] >> ================================================================== >> [ 0.000000] Disabling lock debugging due to kernel taint >> [ 0.000000] MMU: Allocated 76 bytes of context maps for 16 contexts >> [ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 8176 >> [ 0.000000] Kernel command line: console=ttyCPM0,115200N8 >> ip=192.168.2.7:192.168.2.2::255.0.0.0:vgoip:eth0:off kgdboc=ttyCPM0 >> [ 0.000000] Dentry cache hash table entries: 16384 (order: 2, 65536 >> bytes) >> [ 0.000000] Inode-cache hash table entries: 8192 (order: 1, 32768 bytes) >> [ 0.000000] Memory: 99904K/131072K available (7376K kernel code, 528K >> rwdata, 1168K rodata, 576K init, 4623K bss, 31168K reserved, 0K >> cma-reserved) >> [ 0.000000] Kernel virtual memory layout: >> [ 0.000000] * 0xffefc000..0xffffc000 : fixmap >> [ 0.000000] * 0xf7c00000..0xffc00000 : kasan shadow mem >> [ 0.000000] * 0xf7a00000..0xf7c00000 : consistent mem >> [ 0.000000] * 0xf7a00000..0xf7a00000 : early ioremap >> [ 0.000000] * 0xc9000000..0xf7a00000 : vmalloc & ioremap >> >> >> Christophe
| |