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SubjectRe: [PATCH v3 3/3] powerpc/32: Add KASAN support
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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 ?

[ 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

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