# git rev-parse -q --verify 53f1d31708f6240e4615b0927df31f182e389e2f^{commit} 53f1d31708f6240e4615b0927df31f182e389e2f already have revision, skipping fetch # git checkout -q -f -B kisskb 53f1d31708f6240e4615b0927df31f182e389e2f # git clean -qxdf # < git log -1 # commit 53f1d31708f6240e4615b0927df31f182e389e2f # Author: Aneesh Kumar K.V # Date: Fri Mar 26 12:37:55 2021 +0530 # # powerpc/mm/book3s64: Use the correct storage key value when calling H_PROTECT # # H_PROTECT expects the flag value to include flags: # AVPN, pp0, pp1, pp2, key0-key4, Noexec, CMO Option flags # # This patch updates hpte_updatepp() to fetch the storage key value from # the linux page table and use the same in H_PROTECT hcall. # # native_hpte_updatepp() is not updated because the kernel doesn't clear # the existing storage key value there. The kernel also doesn't use # hpte_updatepp() callback for updating storage keys. # # This fixes the below kernel crash observed with KUAP enabled. # # BUG: Unable to handle kernel data access on write at 0xc009fffffc440000 # Faulting instruction address: 0xc0000000000b7030 # Key fault AMR: 0xfcffffffffffffff IAMR: 0xc0000077bc498100 # Found HPTE: v = 0x40070adbb6fffc05 r = 0x1ffffffffff1194 # Oops: Kernel access of bad area, sig: 11 [#1] # LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries # ... # CFAR: c000000000010100 DAR: c009fffffc440000 DSISR: 02200000 IRQMASK: 0 # ... # NIP memset+0x68/0x104 # LR pcpu_alloc+0x54c/0xb50 # Call Trace: # pcpu_alloc+0x55c/0xb50 (unreliable) # blk_stat_alloc_callback+0x94/0x150 # blk_mq_init_allocated_queue+0x64/0x560 # blk_mq_init_queue+0x54/0xb0 # scsi_mq_alloc_queue+0x30/0xa0 # scsi_alloc_sdev+0x1cc/0x300 # scsi_probe_and_add_lun+0xb50/0x1020 # __scsi_scan_target+0x17c/0x790 # scsi_scan_channel+0x90/0xe0 # scsi_scan_host_selected+0x148/0x1f0 # do_scan_async+0x2c/0x2a0 # async_run_entry_fn+0x78/0x220 # process_one_work+0x264/0x540 # worker_thread+0xa8/0x600 # kthread+0x190/0x1a0 # ret_from_kernel_thread+0x5c/0x6c # # With KUAP enabled the kernel uses storage key 3 for all its # translations. But as shown by the debug print, in this specific case we # have the hash page table entry created with key value 0. # # Found HPTE: v = 0x40070adbb6fffc05 r = 0x1ffffffffff1194 # # and DSISR indicates a key fault. # # This can happen due to parallel fault on the same EA by different CPUs: # # CPU 0 CPU 1 # fault on X # # H_PAGE_BUSY set # fault on X # # finish fault handling and # clear H_PAGE_BUSY # check for H_PAGE_BUSY # continue with fault handling. # # This implies CPU1 will end up calling hpte_updatepp for address X and # the kernel updated the hash pte entry with key 0 # # Fixes: d94b827e89dc ("powerpc/book3s64/kuap: Use Key 3 for kernel mapping with hash translation") # Reported-by: Murilo Opsfelder Araujo # Signed-off-by: Aneesh Kumar K.V # Debugged-by: Michael Ellerman # Signed-off-by: Michael Ellerman # Link: https://lore.kernel.org/r/20210326070755.304625-1-aneesh.kumar@linux.ibm.com # < /opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux-gcc --version # < /opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux-ld --version # < git log --format=%s --max-count=1 53f1d31708f6240e4615b0927df31f182e389e2f # < make -s -j 48 ARCH=mips O=/kisskb/build/powerpc-fixes_mips-defconfig_mipsel CROSS_COMPILE=/opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux- defconfig # < make -s -j 48 ARCH=mips O=/kisskb/build/powerpc-fixes_mips-defconfig_mipsel CROSS_COMPILE=/opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux- help # make -s -j 48 ARCH=mips O=/kisskb/build/powerpc-fixes_mips-defconfig_mipsel CROSS_COMPILE=/opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux- olddefconfig # make -s -j 48 ARCH=mips O=/kisskb/build/powerpc-fixes_mips-defconfig_mipsel CROSS_COMPILE=/opt/cross/kisskb/br-mipsel-o32-full-2016.08-613-ge98b4dd/bin/mipsel-linux- FIT description: Linux 5.12.0-rc2-g53f1d31708f6 Created: Sun Mar 28 01:13:30 2021 Image 0 (kernel@0) Description: Linux 5.12.0-rc2-g53f1d31708f6 Created: Sun Mar 28 01:13:30 2021 Type: Kernel Image Compression: gzip compressed Data Size: 5251828 Bytes = 5128.74 KiB = 5.01 MiB Architecture: MIPS OS: Linux Load Address: 0x80100000 Entry Point: 0x809a78c8 Hash algo: sha1 Hash value: 40433160f4f83921ca0f20cb16ac20cd0ba2101d Image 1 (fdt@boston) Description: img,boston Device Tree Created: Sun Mar 28 01:13:30 2021 Type: Flat Device Tree Compression: uncompressed Data Size: 3793 Bytes = 3.70 KiB = 0.00 MiB Architecture: MIPS Hash algo: sha1 Hash value: 4799f50d688573234da6e9d7701234d394759ef4 Image 2 (fdt@ni169445) Description: NI 169445 device tree Created: Sun Mar 28 01:13:30 2021 Type: Flat Device Tree Compression: uncompressed Data Size: 1871 Bytes = 1.83 KiB = 0.00 MiB Architecture: MIPS Hash algo: sha1 Hash value: 51b89b31605ee62038c8468c429af091dfc75ec7 Image 3 (fdt@ocelot_pcb123) Description: MSCC Ocelot PCB123 Device Tree Created: Sun Mar 28 01:13:30 2021 Type: Flat Device Tree Compression: uncompressed Data Size: 4659 Bytes = 4.55 KiB = 0.00 MiB Architecture: MIPS Hash algo: sha1 Hash value: 5bcb6e4f21e8e5372544aa130b3bd097355a9050 Image 4 (fdt@ocelot_pcb120) Description: MSCC Ocelot PCB120 Device Tree Created: Sun Mar 28 01:13:30 2021 Type: Flat Device Tree Compression: uncompressed Data Size: 5418 Bytes = 5.29 KiB = 0.01 MiB Architecture: MIPS Hash algo: sha1 Hash value: 93d882f2009a217e0fa9dab94788535ed2be8476 Image 5 (fdt@xilfpga) Description: MIPSfpga (xilfpga) Device Tree Created: Sun Mar 28 01:13:30 2021 Type: Flat Device Tree Compression: uncompressed Data Size: 2708 Bytes = 2.64 KiB = 0.00 MiB Architecture: MIPS Hash algo: sha1 Hash value: 63d058b780f65e22da30f0a183433765f1807f1d Default Configuration: 'conf@default' Configuration 0 (conf@default) Description: Generic Linux kernel Kernel: kernel@0 Configuration 1 (conf@boston) Description: Boston Linux kernel Kernel: kernel@0 FDT: fdt@boston Configuration 2 (conf@ni169445) Description: NI 169445 Linux Kernel Kernel: kernel@0 FDT: fdt@ni169445 Configuration 3 (conf@ocelot_pcb123) Description: Ocelot Linux kernel Kernel: kernel@0 FDT: fdt@ocelot_pcb123 Configuration 4 (conf@ocelot_pcb120) Description: Ocelot Linux kernel Kernel: kernel@0 FDT: fdt@ocelot_pcb120 Configuration 5 (conf@xilfpga) Description: MIPSfpga Linux kernel Kernel: kernel@0 FDT: fdt@xilfpga Completed OK # rm -rf /kisskb/build/powerpc-fixes_mips-defconfig_mipsel # Build took: 0:01:43.890977