> On 30-Apr-2019, at 1:29 PM, Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com> > wrote: > > 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 racec > between two parallel subpage_prot syscall. > > Reported-by: Sachin Sant <sach...@linux.vnet.ibm.com> > Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com> > —
Thanks for the patch. Fixes the kernel crash. Tested-by: Sachin Sant <sach...@linux.vnet.ibm.com <mailto:sach...@linux.vnet.ibm.com>> Thanks -Sachin
