# git rev-parse -q --verify 4025c784c573cab7e3f84746cc82b8033923ec62^{commit} 4025c784c573cab7e3f84746cc82b8033923ec62 already have revision, skipping fetch # git checkout -q -f -B kisskb 4025c784c573cab7e3f84746cc82b8033923ec62 # git clean -qxdf # < git log -1 # commit 4025c784c573cab7e3f84746cc82b8033923ec62 # Author: Nicholas Piggin # Date: Sat Jan 23 16:12:44 2021 +1000 # # powerpc/64s: prevent recursive replay_soft_interrupts causing superfluous interrupt # # When an asynchronous interrupt calls irq_exit, it checks for softirqs # that may have been created, and runs them. Running softirqs enables # local irqs, which can replay pending interrupts causing recursion in # replay_soft_interrupts. This abridged trace shows how this can occur: # # ! NIP replay_soft_interrupts # LR interrupt_exit_kernel_prepare # Call Trace: # interrupt_exit_kernel_prepare (unreliable) # interrupt_return # --- interrupt: ea0 at __rb_reserve_next # NIP __rb_reserve_next # LR __rb_reserve_next # Call Trace: # ring_buffer_lock_reserve # trace_function # function_trace_call # ftrace_call # __do_softirq # irq_exit # timer_interrupt # ! replay_soft_interrupts # interrupt_exit_kernel_prepare # interrupt_return # --- interrupt: ea0 at arch_local_irq_restore # # This can not be prevented easily, because softirqs must not block hard # irqs, so it has to be dealt with. # # The recursion is bounded by design in the softirq code because softirq # replay disables softirqs and loops around again to check for new # softirqs created while it ran, so that's not a problem. # # However it does mess up interrupt replay state, causing superfluous # interrupts when the second replay_soft_interrupts clears a pending # interrupt, leaving it still set in the first call in the 'happened' # local variable. # # Fix this by not caching a copy of irqs_happened across interrupt # handler calls. # # Fixes: 3282a3da25bd ("powerpc/64: Implement soft interrupt replay in C") # Signed-off-by: Nicholas Piggin # Signed-off-by: Michael Ellerman # Link: https://lore.kernel.org/r/20210123061244.2076145-1-npiggin@gmail.com # < /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 4025c784c573cab7e3f84746cc82b8033923ec62 # < make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_mpc86xx_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- mpc86xx_defconfig # < make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_mpc86xx_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- help # make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_mpc86xx_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- olddefconfig # make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_mpc86xx_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- /kisskb/src/arch/powerpc/boot/dts/fsl/mvme7100.dts:135.22-137.4: Warning (pci_bridge): /pcie@f1008000: missing ranges for PCI bridge (or not a bridge) also defined at /kisskb/src/arch/powerpc/boot/dts/fsl/mpc8641si-post.dtsi:92.7-117.3 /kisskb/src/arch/powerpc/boot/dts/fsl/mpc8641si-post.dtsi:102.9-116.4: Warning (pci_bridge): /pcie@f1008000/pcie@0: missing ranges for PCI bridge (or not a bridge) /kisskb/src/arch/powerpc/boot/dts/fsl/mvme7100.dts:139.22-141.4: Warning (pci_bridge): /pcie@f1009000: missing ranges for PCI bridge (or not a bridge) also defined at /kisskb/src/arch/powerpc/boot/dts/fsl/mpc8641si-post.dtsi:119.7-144.3 /kisskb/src/arch/powerpc/boot/dts/fsl/mpc8641si-post.dtsi:129.9-143.4: Warning (pci_bridge): /pcie@f1009000/pcie@0: missing ranges for PCI bridge (or not a bridge) arch/powerpc/boot/dts/fsl/mvme7100.dtb: Warning (pci_device_bus_num): Failed prerequisite 'pci_bridge' /kisskb/src/arch/powerpc/boot/dts/fsl/mvme7100.dts:30.11-32.6: Warning (i2c_bus_reg): /soc@f1000000/i2c@3000/rtc@68: missing or empty reg property INFO: Uncompressed kernel (size 0xc622a0) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xd00000) Image Name: Linux-5.11.0-rc2-g4025c784c573 Created: Sun Jan 24 22:48:58 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 5654138 Bytes = 5521.62 KiB = 5.39 MiB Load Address: 00000000 Entry Point: 00000000 Completed OK # rm -rf /kisskb/build/powerpc-fixes_mpc86xx_defconfig_powerpc-gcc5 # Build took: 0:02:07.730559