# git rev-parse -q --verify 3fa6fc04815a70a110445368c8741c178970c87d^{commit} 3fa6fc04815a70a110445368c8741c178970c87d already have revision, skipping fetch # git checkout -q -f -B kisskb 3fa6fc04815a70a110445368c8741c178970c87d # git clean -qxdf # < git log -1 # commit 3fa6fc04815a70a110445368c8741c178970c87d # Author: Michael Ellerman # Date: Sun May 3 00:33:16 2020 +1000 # # powerpc/64s: Fix unrecoverable SLB crashes due to preemption check # # Hugh reported that his trusty G5 crashed after a few hours under load # with an "Unrecoverable exception 380". # # The crash is in interrupt_return() where we check lazy_irq_pending(), # which calls get_paca() and with CONFIG_DEBUG_PREEMPT=y that goes to # check_preemption_disabled() via debug_smp_processor_id(). # # As Nick explained on the list: # # Problem is MSR[RI] is cleared here, ready to do the last few things # for interrupt return where we're not allowed to take any other # interrupts. # # SLB interrupts can happen just about anywhere aside from kernel # text, global variables, and stack. When that hits, it appears to be # unrecoverable due to RI=0. # # The problematic access is in preempt_count() which is: # # return READ_ONCE(current_thread_info()->preempt_count); # # Because of THREAD_INFO_IN_TASK, current_thread_info() just points to # current, so the access is to somewhere in kernel memory, but not on # the stack or in .data, which means it can cause an SLB miss. If we # take an SLB miss with RI=0 it is fatal. # # The easiest solution is to add a version of lazy_irq_pending() that # doesn't do the preemption check and call it from the interrupt return # path. # # Fixes: 68b34588e202 ("powerpc/64/sycall: Implement syscall entry/exit logic in C") # Reported-by: Hugh Dickins # Signed-off-by: Michael Ellerman # Signed-off-by: Michael Ellerman # Link: https://lore.kernel.org/r/20200502143316.929341-1-mpe@ellerman.id.au # < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-gcc --version # < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-ld --version # < git log --format=%s --max-count=1 3fa6fc04815a70a110445368c8741c178970c87d # < make -s -j 24 ARCH=powerpc O=/kisskb/build/powerpc-fixes_mpc85xx_smp_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- mpc85xx_smp_defconfig # < make -s -j 24 ARCH=powerpc O=/kisskb/build/powerpc-fixes_mpc85xx_smp_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- help # make -s -j 24 ARCH=powerpc O=/kisskb/build/powerpc-fixes_mpc85xx_smp_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- olddefconfig # make -s -j 24 ARCH=powerpc O=/kisskb/build/powerpc-fixes_mpc85xx_smp_defconfig_powerpc-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux- /kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl': /kisskb/src/kernel/printk/printk.c:204:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/proc/inode.c: In function 'proc_reg_open': /kisskb/src/include/linux/list.h:72:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/proc/inode.c:471:21: note: 'pdeo' was declared here /kisskb/src/mm/hugetlb.c: In function 'alloc_pool_huge_page': /kisskb/src/mm/hugetlb.c:1774:5: warning: 'page' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/kernel/trace/trace_events.c: In function 'event_create_dir': /kisskb/src/kernel/trace/trace_events.c:2189:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/sound/soc/codecs/wm8960.c: In function 'wm8960_configure_clocking': /kisskb/src/sound/soc/codecs/wm8960.c:800:70: warning: 'j' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/sound/soc/codecs/wm8960.c:797:68: warning: 'i' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/ext4/extents.c: In function 'ext4_convert_unwritten_io_end_vec': /kisskb/src/fs/ext4/extents.c:4774:23: warning: 'ret' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/tty/serial/8250/8250_core.c: In function 'univ8250_release_irq': /kisskb/src/drivers/tty/serial/8250/8250_core.c:247:18: warning: 'i' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/tty/serial/8250/8250_core.c:227:19: note: 'i' was declared here /kisskb/src/fs/namei.c: In function 'handle_dots': /kisskb/src/fs/namei.c:1805:10: warning: 'inode' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/namei.c:1805:10: warning: 'seq' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/base/regmap/regmap.c: In function 'regmap_raw_read': /kisskb/src/drivers/base/regmap/regmap.c:2598:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/base/regmap/regmap.c: In function '_regmap_raw_write': /kisskb/src/drivers/base/regmap/regmap.c:1859:6: warning: 'ret' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/udf/unicode.c: In function 'udf_name_conv_char': /kisskb/src/fs/udf/unicode.c:132:8: warning: 'c' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/fs/io_uring.c: In function '__io_sqe_files_update': /kisskb/src/fs/io_uring.c:6701:13: warning: 'err' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/drivers/net/ethernet/freescale/fs_enet/mac-scc.c: In function 'allocate_bd': /kisskb/src/drivers/net/ethernet/freescale/fs_enet/mac-scc.c:139:6: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast] /kisskb/src/drivers/usb/core/devio.c: In function 'async_completed': /kisskb/src/drivers/usb/core/devio.c:625:23: warning: 'errno' may be used uninitialized in this function [-Wuninitialized] /kisskb/src/arch/powerpc/boot/dts/fsl/mpc8541cds.dts:330.3-21: Warning (pci_device_bus_num): /pci@e0008000/i8259@19000:bus-range: PCI bus number 1 out of range, expected (0 - 0) /kisskb/src/arch/powerpc/boot/dts/fsl/mpc8555cds.dts:330.3-21: Warning (pci_device_bus_num): /pci@e0008000/i8259@19000:bus-range: PCI bus number 1 out of range, expected (0 - 0) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd42728) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd31f58) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:34 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6405157 Bytes = 6255.04 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002a8 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:34 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6404962 Bytes = 6254.85 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002a8 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:34 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6373778 Bytes = 6224.39 KiB = 6.08 MiB Load Address: 00000000 Entry Point: 00000000 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:34 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6404354 Bytes = 6254.25 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002e8 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:34 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6406371 Bytes = 6256.22 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002a8 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:34 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6404994 Bytes = 6254.88 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002e8 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:34 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6406153 Bytes = 6256.01 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002a8 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:34 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6406372 Bytes = 6256.22 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002a8 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:34 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6405056 Bytes = 6254.94 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002e8 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:34 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6404249 Bytes = 6254.15 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002a8 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:34 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6404261 Bytes = 6254.16 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002e8 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:34 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6404955 Bytes = 6254.84 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002a8 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:34 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6406288 Bytes = 6256.14 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002a8 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:35 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6405244 Bytes = 6255.12 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002a8 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:34 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6404356 Bytes = 6254.25 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002a8 Image Name: Linux-5.7.0-rc2-g3fa6fc04815a Created: Mon May 4 13:39:35 2020 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6404260 Bytes = 6254.16 KiB = 6.11 MiB Load Address: 00e00000 Entry Point: 00e002e8 Completed OK # rm -rf /kisskb/build/powerpc-fixes_mpc85xx_smp_defconfig_powerpc-gcc4.6 # Build took: 0:02:16.635690