# git rev-parse -q --verify 02bcfdb19fb56060fe0e1ddfede51d0379097a46^{commit} 02bcfdb19fb56060fe0e1ddfede51d0379097a46 already have revision, skipping fetch # git checkout -q -f -B kisskb 02bcfdb19fb56060fe0e1ddfede51d0379097a46 # git clean -qxdf # < git log -1 # commit 02bcfdb19fb56060fe0e1ddfede51d0379097a46 # Author: Christophe Leroy # Date: Wed Aug 18 06:49:29 2021 +0000 # # powerpc/32s: Fix random crashes by adding isync() after locking/unlocking KUEP # # Commit b5efec00b671 ("powerpc/32s: Move KUEP locking/unlocking in C") # removed the 'isync' instruction after adding/removing NX bit in user # segments. The reasoning behind this change was that when setting the # NX bit we don't mind it taking effect with delay as the kernel never # executes text from userspace, and when clearing the NX bit this is # to return to userspace and then the 'rfi' should synchronise the # context. # # However, it looks like on book3s/32 having a hash page table, at least # on the G3 processor, we get an unexpected fault from userspace, then # this is followed by something wrong in the verification of MSR_PR # at end of another interrupt. # # This is fixed by adding back the removed isync() following update # of NX bit in user segment registers. Only do it for cores with an # hash table, as 603 cores don't exhibit that problem and the two isync # increase ./null_syscall selftest by 6 cycles on an MPC 832x. # # First problem: unexpected WARN_ON() for mysterious PROTFAULT # # WARNING: CPU: 0 PID: 1660 at arch/powerpc/mm/fault.c:354 do_page_fault+0x6c/0x5b0 # Modules linked in: # CPU: 0 PID: 1660 Comm: Xorg Not tainted 5.13.0-pmac-00028-gb3c15b60339a #40 # NIP: c001b5c8 LR: c001b6f8 CTR: 00000000 # REGS: e2d09e40 TRAP: 0700 Not tainted (5.13.0-pmac-00028-gb3c15b60339a) # MSR: 00021032 CR: 42d04f30 XER: 20000000 # GPR00: c000424c e2d09f00 c301b680 e2d09f40 0000001e 42000000 00cba028 00000000 # GPR08: 08000000 48000010 c301b680 e2d09f30 22d09f30 00c1fff0 00cba000 a7b7ba4c # GPR16: 00000031 00000000 00000000 00000000 00000000 00000000 a7b7b0d0 00c5c010 # GPR24: a7b7b64c a7b7d2f0 00000004 00000000 c1efa6c0 00cba02c 00000300 e2d09f40 # NIP [c001b5c8] do_page_fault+0x6c/0x5b0 # LR [c001b6f8] do_page_fault+0x19c/0x5b0 # Call Trace: # [e2d09f00] [e2d09f04] 0xe2d09f04 (unreliable) # [e2d09f30] [c000424c] DataAccess_virt+0xd4/0xe4 # --- interrupt: 300 at 0xa7a261dc # NIP: a7a261dc LR: a7a253bc CTR: 00000000 # REGS: e2d09f40 TRAP: 0300 Not tainted (5.13.0-pmac-00028-gb3c15b60339a) # MSR: 0000d032 CR: 228428e2 XER: 20000000 # DAR: 00cba02c DSISR: 42000000 # GPR00: a7a27448 afa6b0e0 a74c35c0 a7b7b614 0000001e a7b7b614 00cba028 00000000 # GPR08: 00020fd9 00000031 00cb9ff8 a7a273b0 220028e2 00c1fff0 00cba000 a7b7ba4c # GPR16: 00000031 00000000 00000000 00000000 00000000 00000000 a7b7b0d0 00c5c010 # GPR24: a7b7b64c a7b7d2f0 00000004 00000002 0000001e a7b7b614 a7b7aff4 00000030 # NIP [a7a261dc] 0xa7a261dc # LR [a7a253bc] 0xa7a253bc # --- interrupt: 300 # Instruction dump: # 7c4a1378 810300a0 75278410 83820298 83a300a4 553b018c 551e0036 4082038c # 2e1b0000 40920228 75280800 41820220 <0fe00000> 3b600000 41920214 81420594 # # Second problem: MSR PR is seen unset allthough the interrupt frame shows it set # # kernel BUG at arch/powerpc/kernel/interrupt.c:458! # Oops: Exception in kernel mode, sig: 5 [#1] # BE PAGE_SIZE=4K MMU=Hash SMP NR_CPUS=2 PowerMac # Modules linked in: # CPU: 0 PID: 1660 Comm: Xorg Tainted: G W 5.13.0-pmac-00028-gb3c15b60339a #40 # NIP: c0011434 LR: c001629c CTR: 00000000 # REGS: e2d09e70 TRAP: 0700 Tainted: G W (5.13.0-pmac-00028-gb3c15b60339a) # MSR: 00029032 CR: 42d09f30 XER: 00000000 # GPR00: 00000000 e2d09f30 c301b680 e2d09f40 83440000 c44d0e68 e2d09e8c 00000000 # GPR08: 00000002 00dc228a 00004000 e2d09f30 22d09f30 00c1fff0 afa6ceb4 00c26144 # GPR16: 00c25fb8 00c26140 afa6ceb8 90000000 00c944d8 0000001c 00000000 00200000 # GPR24: 00000000 000001fb afa6d1b4 00000001 00000000 a539a2a0 a530fd80 00000089 # NIP [c0011434] interrupt_exit_kernel_prepare+0x10/0x70 # LR [c001629c] interrupt_return+0x9c/0x144 # Call Trace: # [e2d09f30] [c000424c] DataAccess_virt+0xd4/0xe4 (unreliable) # --- interrupt: 300 at 0xa09be008 # NIP: a09be008 LR: a09bdfe8 CTR: a09bdfc0 # REGS: e2d09f40 TRAP: 0300 Tainted: G W (5.13.0-pmac-00028-gb3c15b60339a) # MSR: 0000d032 CR: 420028e2 XER: 20000000 # DAR: a539a308 DSISR: 0a000000 # GPR00: a7b90d50 afa6b2d0 a74c35c0 a0a8b690 a0a8b698 a5365d70 a4fa82a8 00000004 # GPR08: 00000000 a09bdfc0 00000000 a5360000 a09bde7c 00c1fff0 afa6ceb4 00c26144 # GPR16: 00c25fb8 00c26140 afa6ceb8 90000000 00c944d8 0000001c 00000000 00200000 # GPR24: 00000000 000001fb afa6d1b4 00000001 00000000 a539a2a0 a530fd80 00000089 # NIP [a09be008] 0xa09be008 # LR [a09bdfe8] 0xa09bdfe8 # --- interrupt: 300 # Instruction dump: # 80010024 83e1001c 7c0803a6 4bffff80 3bc00800 4bffffd0 486b42fd 4bffffcc # 81430084 71480002 41820038 554a0462 <0f0a0000> 80620060 74630001 40820034 # # Fixes: b5efec00b671 ("powerpc/32s: Move KUEP locking/unlocking in C") # Cc: stable@vger.kernel.org # v5.13+ # Reported-by: Stan Johnson # Signed-off-by: Christophe Leroy # Signed-off-by: Michael Ellerman # Link: https://lore.kernel.org/r/4856f5574906e2aec0522be17bf3848a22b2cd0b.1629269345.git.christophe.leroy@csgroup.eu # < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version # < git log --format=%s --max-count=1 02bcfdb19fb56060fe0e1ddfede51d0379097a46 # < make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_85xx_stx_gp3_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- 85xx/stx_gp3_defconfig # < make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_85xx_stx_gp3_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- help # make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_85xx_stx_gp3_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- olddefconfig # make -s -j 120 ARCH=powerpc O=/kisskb/build/powerpc-fixes_85xx_stx_gp3_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- Completed OK # rm -rf /kisskb/build/powerpc-fixes_85xx_stx_gp3_defconfig_powerpc-gcc5 # Build took: 0:00:44.561466