Buildresult: powerpc-next/85xx/sbc8548_defconfig/powerpc-gcc4.9 built on Jul 17 2021, 18:02

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Status:	OK
Date/Time:	Jul 17 2021, 18:02
Duration:	0:00:49.259827
Builder:	ka3
Revision:	powerpc/stacktrace: Fix spurious "stale" traces in raise_backtrace_ipi() (`7c6986ade69e3c81bac831645bc72109cd798a80)`
Target:	powerpc-next/85xx/sbc8548_defconfig/powerpc-gcc4.9
Branch:	powerpc-next
Compiler:	powerpc-gcc4.9 (powerpc64-linux-gcc (GCC) 4.9.4 / GNU ld (GNU Binutils) 2.29.1.20170915)
Config:	85xx/sbc8548_defconfig (download)
Log:	Download original Possible warnings (2) net/sched/sch_frag.c:93:10: warning: missing braces around initializer [-Wmissing-braces] net/sched/sch_frag.c:93:10: warning: (near initialization for 'sch_frag_rt.dst') [-Wmissing-braces] Full Log # 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 <mpe@ellerman.id.au> # 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 <nathanl@linux.ibm.com> # Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> # 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 80 ARCH=powerpc O=/kisskb/build/powerpc-next_85xx_sbc8548_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux- 85xx/sbc8548_defconfig # < make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-next_85xx_sbc8548_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux- help # make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-next_85xx_sbc8548_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux- olddefconfig # make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-next_85xx_sbc8548_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] INFO: Uncompressed kernel (size 0x4fd354) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x500000) INFO: Uncompressed kernel (size 0x4ecd6c) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x500000) Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 18:03:29 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 2543951 Bytes = 2484.33 KiB = 2.43 MiB Load Address: 00000000 Entry Point: 00000000 Image Name: Linux-5.13.0-rc2-g7c6986ade69e Created: Sat Jul 17 18:03:30 2021 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 2574225 Bytes = 2513.89 KiB = 2.45 MiB Load Address: 00500000 Entry Point: 005002a4 Completed OK # rm -rf /kisskb/build/powerpc-next_85xx_sbc8548_defconfig_powerpc-gcc4.9 # Build took: 0:00:49.259827

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