Re: [PATCH] powerpc: don't select KFENCE on platform PPC_FSL_BOOK3E
From: LEROY Christophe <hidden>
Date: 2021-10-12 05:41:40
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Le 12/10/2021 à 03:43, Liu Shixin a écrit :
kindly ping.
Hi Based on the discussion we had, this patch is not enough. It should at least also de-activate DEBUG_PAGEALLOC, However I'm looking at fixing it the other way round. Give me one week or two. Christophe
On 2021/9/24 14:39, Liu Shixin wrote:quoted
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: 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 <redacted> --- 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