path: root/arch/powerpc/mm/40x_mmu.c
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authorAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>2019-04-30 13:29:07 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2019-05-01 23:01:33 +1000
commit2c474c03505677cfd987d52e8bf42abe8c270529 (patch)
tree7e61a1fce88414d9400c3f71668e7db390f8daf7 /arch/powerpc/mm/40x_mmu.c
parentpowerpc/powernv/mce: Print additional information about MCE error. (diff)
powerpc/mm/radix: Fix kernel crash when running subpage protect test
This patch fixes the below crash by making sure we touch the subpage protection related structures only if we know they are allocated on the platform. With radix translation we don't allocate hash context at all and trying to access subpage_prot_table results in: Faulting instruction address: 0xc00000000008bdb4 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix MMU=Hash SMP NR_CPUS=2048 NUMA PowerNV .... NIP [c00000000008bdb4] sys_subpage_prot+0x74/0x590 LR [c00000000000b688] system_call+0x5c/0x70 Call Trace: [c00020002c6b7d30] [c00020002c6b7d90] 0xc00020002c6b7d90 (unreliable) [c00020002c6b7e20] [c00000000000b688] system_call+0x5c/0x70 Instruction dump: fb61ffd8 fb81ffe0 fba1ffe8 fbc1fff0 fbe1fff8 f821ff11 e92d1178 f9210068 39200000 e92d0968 ebe90630 e93f03e8 <eb891038> 60000000 3860fffe e9410068 We also move the subpage_prot_table with mmp_sem held to avoid race between two parallel subpage_prot syscall. Fixes: 701101865f5d ("powerpc/mm: Reduce memory usage for mm_context_t for radix") Reported-by: Sachin Sant <sachinp@linux.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Tested-by: Sachin Sant <sachinp@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/mm/40x_mmu.c')
0 files changed, 0 insertions, 0 deletions