Messages in this thread Patch in this message | | | Subject | Re: [PATCH] powerpc: don't select KFENCE on platform PPC_FSL_BOOK3E | From | Liu Shixin <> | Date | Tue, 28 Sep 2021 11:06:58 +0800 |
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On 2021/9/24 14:41, Christophe Leroy wrote: > > > Le 24/09/2021 à 08:39, Liu Shixin a écrit : >> On platform PPC_FSL_BOOK3E, all lowmem is managed by tlbcam. That means >> we didn't really map the kfence pool with page granularity. Therefore, >> if KFENCE is enabled, the system will hit the following panic: > > Could you please explain a bit more what the problem is ? > > KFENCE has been implemented with the same logic as DEBUG_PAGEALLOC. > > DEBUG_PAGEALLOC is enabled on FSL_BOOK3E. > > In MMU_setup(), __map_without_ltlbs is set to 1 when KFENCE is enabled. > > __map_without_ltlbs should disable the use of tlbcam. > > > So what's wrong really ? > > Does DEBUG_PAGEALLOC work on FSL_BOOK3E ? > > Thanks > Christophe hi Christophe,
In the last e-mail I have said that DEBUG_PAGEALLOC works well on FSL_BOOK3E, that is wrong. Actually, I add some printed information and find DEBUG_PAGEALLOC Skip all pages. So neither DEBUG_PAGEALLOC nor kfence is really working.
diff --git a/mm/memory.c b/mm/memory.c index 25fc46e87214..37fb1b14bc3f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2564,8 +2564,10 @@ static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, } do { next = pmd_addr_end(addr, end); - if (pmd_none(*pmd) && !create) + if (pmd_none(*pmd) && !create) { + pr_info("---------pmd_none----------\n"); continue; + } if (WARN_ON_ONCE(pmd_leaf(*pmd))) return -EINVAL; if (!pmd_none(*pmd) && WARN_ON_ONCE(pmd_bad(*pmd))) { > >> >> BUG: Kernel NULL pointer dereference on read at 0x00000000 >> Faulting instruction address: 0xc01de598 >> Oops: Kernel access of bad area, sig: 11 [#1] >> BE PAGE_SIZE=4K SMP NR_CPUS=4 MPC8544 DS >> Dumping ftrace buffer: >> (ftrace buffer empty) >> Modules linked in: >> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc3+ #298 >> NIP: c01de598 LR: c08ae9c4 CTR: 00000000 >> REGS: c0b4bea0 TRAP: 0300 Not tainted (5.12.0-rc3+) >> MSR: 00021000 <CE,ME> CR: 24000228 XER: 20000000 >> DEAR: 00000000 ESR: 00000000 >> GPR00: c08ae9c4 c0b4bf60 c0ad64e0 ef720000 00021000 00000000 00000000 00000200 >> GPR08: c0ad5000 00000000 00000000 00000004 00000000 008fbb30 00000000 00000000 >> GPR16: 00000000 00000000 00000000 00000000 c0000000 00000000 00000000 00000000 >> GPR24: c08ca004 c08ca004 c0b6a0e0 c0b60000 c0b58f00 c0850000 c08ca000 ef720000 >> NIP [c01de598] kfence_protect+0x44/0x6c >> LR [c08ae9c4] kfence_init+0xfc/0x2a4 >> Call Trace: >> [c0b4bf60] [efffe160] 0xefffe160 (unreliable) >> [c0b4bf70] [c08ae9c4] kfence_init+0xfc/0x2a4 >> [c0b4bfb0] [c0894d3c] start_kernel+0x3bc/0x574 >> [c0b4bff0] [c0000470] set_ivor+0x14c/0x188 >> Instruction dump: >> 7c0802a6 8109d594 546a653a 90010014 54630026 39200000 7d48502e 2c0a0000 >> 41820010 554a0026 5469b53a 7d295214 <81490000> 38831000 554a003c 91490000 >> random: get_random_bytes called from print_oops_end_marker+0x40/0x78 with crng_init=0 >> ---[ end trace 0000000000000000 ]--- >> >> Signed-off-by: Liu Shixin <liushixin2@huawei.com> >> --- >> arch/powerpc/Kconfig | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig >> index d46db0bfb998..cffd57bcb5e4 100644 >> --- a/arch/powerpc/Kconfig >> +++ b/arch/powerpc/Kconfig >> @@ -185,7 +185,7 @@ config PPC >> select HAVE_ARCH_KASAN if PPC32 && PPC_PAGE_SHIFT <= 14 >> select HAVE_ARCH_KASAN_VMALLOC if PPC32 && PPC_PAGE_SHIFT <= 14 >> select HAVE_ARCH_KGDB >> - select HAVE_ARCH_KFENCE if PPC32 >> + select HAVE_ARCH_KFENCE if PPC32 && !PPC_FSL_BOOK3E >> select HAVE_ARCH_MMAP_RND_BITS >> select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT >> select HAVE_ARCH_NVRAM_OPS >> > . >
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