# git rev-parse -q --verify 7c6986ade69e3c81bac831645bc72109cd798a80^{commit} 7c6986ade69e3c81bac831645bc72109cd798a80 already have revision, skipping fetch # git checkout -q -f -B kisskb 7c6986ade69e3c81bac831645bc72109cd798a80 # git clean -qxdf # < git log -1 # commit 7c6986ade69e3c81bac831645bc72109cd798a80 # Author: Michael Ellerman # Date: Fri Jun 25 16:28:41 2021 +1000 # # powerpc/stacktrace: Fix spurious "stale" traces in raise_backtrace_ipi() # # In raise_backtrace_ipi() we iterate through the cpumask of CPUs, sending # each an IPI asking them to do a backtrace, but we don't wait for the # backtrace to happen. # # We then iterate through the CPU mask again, and if any CPU hasn't done # the backtrace and cleared itself from the mask, we print a trace on its # behalf, noting that the trace may be "stale". # # This works well enough when a CPU is not responding, because in that # case it doesn't receive the IPI and the sending CPU is left to print the # trace. But when all CPUs are responding we are left with a race between # the sending and receiving CPUs, if the sending CPU wins the race then it # will erroneously print a trace. # # This leads to spurious "stale" traces from the sending CPU, which can # then be interleaved messily with the receiving CPU, note the CPU # numbers, eg: # # [ 1658.929157][ C7] rcu: Stack dump where RCU GP kthread last ran: # [ 1658.929223][ C7] Sending NMI from CPU 7 to CPUs 1: # [ 1658.929303][ C1] NMI backtrace for cpu 1 # [ 1658.929303][ C7] CPU 1 didn't respond to backtrace IPI, inspecting paca. # [ 1658.929362][ C1] CPU: 1 PID: 325 Comm: kworker/1:1H Tainted: G W E 5.13.0-rc2+ #46 # [ 1658.929405][ C7] irq_soft_mask: 0x01 in_mce: 0 in_nmi: 0 current: 325 (kworker/1:1H) # [ 1658.929465][ C1] Workqueue: events_highpri test_work_fn [test_lockup] # [ 1658.929549][ C7] Back trace of paca->saved_r1 (0xc0000000057fb400) (possibly stale): # [ 1658.929592][ C1] NIP: c00000000002cf50 LR: c008000000820178 CTR: c00000000002cfa0 # # To fix it, change the logic so that the sending CPU waits 5s for the # receiving CPU to print its trace. If the receiving CPU prints its trace # successfully then the sending CPU just continues, avoiding any spurious # "stale" trace. # # This has the added benefit of allowing all CPUs to print their traces in # order and avoids any interleaving of their output. # # Fixes: 5cc05910f26e ("powerpc/64s: Wire up arch_trigger_cpumask_backtrace()") # Cc: stable@vger.kernel.org # v4.18+ # Reported-by: Nathan Lynch # Signed-off-by: Michael Ellerman # Link: https://lore.kernel.org/r/20210625140408.3351173-1-mpe@ellerman.id.au # < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version # < git log --format=%s --max-count=1 7c6986ade69e3c81bac831645bc72109cd798a80 # < make -s -j 160 ARCH=powerpc O=/kisskb/build/powerpc-next_mpc85xx_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux- mpc85xx_defconfig # < make -s -j 160 ARCH=powerpc O=/kisskb/build/powerpc-next_mpc85xx_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux- help # make -s -j 160 ARCH=powerpc O=/kisskb/build/powerpc-next_mpc85xx_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux- olddefconfig # make -s -j 160 ARCH=powerpc O=/kisskb/build/powerpc-next_mpc85xx_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux- /kisskb/src/net/sched/sch_frag.c: In function 'sch_fragment': /kisskb/src/net/sched/sch_frag.c:93:10: warning: missing braces around initializer [-Wmissing-braces] struct rtable sch_frag_rt = { 0 }; ^ /kisskb/src/net/sched/sch_frag.c:93:10: warning: (near initialization for 'sch_frag_rt.dst') [-Wmissing-braces] In file included from /kisskb/src/include/linux/kernel.h:11:0, from /kisskb/src/include/linux/list.h:9, from /kisskb/src/include/linux/module.h:12, from /kisskb/src/drivers/net/ethernet/freescale/fs_enet/mac-scc.c:15: /kisskb/src/drivers/net/ethernet/freescale/fs_enet/mac-scc.c: In function 'allocate_bd': /kisskb/src/include/linux/err.h:22:49: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast] #define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) ^ /kisskb/src/include/linux/compiler.h:78:42: note: in definition of macro 'unlikely' # define unlikely(x) __builtin_expect(!!(x), 0) ^ /kisskb/src/drivers/net/ethernet/freescale/fs_enet/mac-scc.c:139:6: note: in expansion of macro 'IS_ERR_VALUE' if (IS_ERR_VALUE(fep->ring_mem_addr)) ^ /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) /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) INFO: Uncompressed kernel (size 0xd72f08) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd72f08) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd72f08) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd72f08) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd72f08) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd72f08) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd72f08) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd72f08) overlaps the address of the wrapper(0x400000) INFO: Uncompressed kernel (size 0xd72f08) 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 0xd72f08) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd72f08) overlaps the address of the wrapper(0x400000) INFO: Uncompressed kernel (size 0xd72f08) 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 0xd72f08) overlaps the address of the wrapper(0x400000) INFO: Uncompressed kernel (size 0xd72f08) 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 0xd72f08) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) INFO: Uncompressed kernel (size 0xd627dc) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0xe00000) Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:28 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6542485 Bytes = 6389.15 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e002a4 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:28 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6509561 Bytes = 6356.99 KiB = 6.21 MiB Load Address: 00000000 Entry Point: 00000000 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:28 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6542293 Bytes = 6388.96 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e002a4 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:29 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6541127 Bytes = 6387.82 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e002a4 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:29 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6541175 Bytes = 6387.87 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e00314 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:30 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6541061 Bytes = 6387.75 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e002a4 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:30 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6543168 Bytes = 6389.81 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e002a4 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:30 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6542165 Bytes = 6388.83 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e002a4 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:30 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6543210 Bytes = 6389.85 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e002a4 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:30 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6541110 Bytes = 6387.80 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e00314 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:30 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6542256 Bytes = 6388.92 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e00314 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:30 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6541620 Bytes = 6388.30 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e00314 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:30 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6542165 Bytes = 6388.83 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e002a4 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:30 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6542193 Bytes = 6388.86 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e002a4 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:30 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6541109 Bytes = 6387.80 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e00314 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 17:57:30 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 6540981 Bytes = 6387.68 KiB = 6.24 MiB Load Address: 00e00000 Entry Point: 00e002a4 Completed OK # rm -rf /kisskb/build/powerpc-next_mpc85xx_defconfig_powerpc-gcc4.9 # Build took: 0:00:52.386651