Buildresult: powerpc-fixes/ia64-defconfig/ia64-gcc4.9 built on May 4 2020, 16:35

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Status:	OK
Date/Time:	May 4 2020, 16:35
Duration:	0:04:18.813526
Builder:	ka3
Revision:	powerpc/64s: Fix unrecoverable SLB crashes due to preemption check (`3fa6fc04815a70a110445368c8741c178970c87d)`
Target:	powerpc-fixes/ia64-defconfig/ia64-gcc4.9
Branch:	powerpc-fixes
Compiler:	ia64-gcc4.9 (ia64-linux-gcc (GCC) 4.9.4 / GNU ld (GNU Binutils) 2.29.1.20170915)
Config:	defconfig (download)
Log:	Download original Possible warnings (6) <stdin>:1511:2: warning: #warning syscall clone3 not implemented [-Wcpp] kernel/futex.c:1676:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized] arch/ia64/include/uapi/asm/cmpxchg.h:57:2: warning: value computed is not used [-Wunused-value] arch/ia64/include/uapi/asm/cmpxchg.h:57:2: warning: value computed is not used [-Wunused-value] drivers/gpu/drm/drm_dp_mst_topology.c:5497:9: warning: missing braces around initializer [-Wmissing-braces] drivers/gpu/drm/drm_dp_mst_topology.c:5497:9: warning: (near initialization for 'desc.ident') [-Wmissing-braces] Full Log # 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 <mpe@ellerman.id.au> # 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 <hughd@google.com> # Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> # Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> # Link: https://lore.kernel.org/r/20200502143316.929341-1-mpe@ellerman.id.au # < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/ia64-linux/bin/ia64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/ia64-linux/bin/ia64-linux-ld --version # < git log --format=%s --max-count=1 3fa6fc04815a70a110445368c8741c178970c87d # < make -s -j 10 ARCH=ia64 O=/kisskb/build/powerpc-fixes_ia64-defconfig_ia64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/ia64-linux/bin/ia64-linux- defconfig # < make -s -j 10 ARCH=ia64 O=/kisskb/build/powerpc-fixes_ia64-defconfig_ia64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/ia64-linux/bin/ia64-linux- help # make -s -j 10 ARCH=ia64 O=/kisskb/build/powerpc-fixes_ia64-defconfig_ia64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/ia64-linux/bin/ia64-linux- olddefconfig # make -s -j 10 ARCH=ia64 O=/kisskb/build/powerpc-fixes_ia64-defconfig_ia64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/ia64-linux/bin/ia64-linux- <stdin>:1511:2: warning: #warning syscall clone3 not implemented [-Wcpp] /kisskb/src/kernel/futex.c: In function 'do_futex': /kisskb/src/kernel/futex.c:1676:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized] return oldval == cmparg; ^ /kisskb/src/kernel/futex.c:1652:6: note: 'oldval' was declared here int oldval, ret; ^ In file included from /kisskb/src/arch/ia64/include/uapi/asm/intrinsics.h:22:0, from /kisskb/src/arch/ia64/include/asm/intrinsics.h:11, from /kisskb/src/arch/ia64/include/asm/bitops.h:19, from /kisskb/src/include/linux/bitops.h:29, from /kisskb/src/include/linux/kernel.h:12, from /kisskb/src/include/linux/list.h:9, from /kisskb/src/include/linux/preempt.h:11, from /kisskb/src/include/linux/spinlock.h:51, from /kisskb/src/include/linux/seqlock.h:36, from /kisskb/src/include/linux/time.h:6, from /kisskb/src/fs/nfs/read.c:11: /kisskb/src/fs/nfs/read.c: In function 'nfs_read_completion': /kisskb/src/arch/ia64/include/uapi/asm/cmpxchg.h:57:2: warning: value computed is not used [-Wunused-value] ((__typeof__((ptr))) __xchg((unsigned long) (x), (ptr), sizeof((ptr)))) ^ /kisskb/src/fs/nfs/read.c:196:5: note: in expansion of macro 'xchg' xchg(&nfs_req_openctx(req)->error, error); ^ /kisskb/src/fs/nfs/read.c: In function 'nfs_readpage': /kisskb/src/arch/ia64/include/uapi/asm/cmpxchg.h:57:2: warning: value computed is not used [-Wunused-value] ((__typeof__((ptr))) __xchg((unsigned long) (x), (ptr), sizeof((ptr)))) ^ /kisskb/src/fs/nfs/read.c:353:2: note: in expansion of macro 'xchg' xchg(&ctx->error, 0); ^ /kisskb/src/drivers/gpu/drm/drm_dp_mst_topology.c: In function 'drm_dp_mst_dsc_aux_for_port': /kisskb/src/drivers/gpu/drm/drm_dp_mst_topology.c:5497:9: warning: missing braces around initializer [-Wmissing-braces] struct drm_dp_desc desc = { 0 }; ^ /kisskb/src/drivers/gpu/drm/drm_dp_mst_topology.c:5497:9: warning: (near initialization for 'desc.ident') [-Wmissing-braces] No errors detected in 22168 functions. Completed OK # rm -rf /kisskb/build/powerpc-fixes_ia64-defconfig_ia64-gcc4.9 # Build took: 0:04:18.813526

© Michael Ellerman 2006-2018.