# git rev-parse -q --verify 2d9cdedc4bdfec9a9d484d3564a1153c3f76ae2d^{commit}
2d9cdedc4bdfec9a9d484d3564a1153c3f76ae2d
already have revision, skipping fetch
# git checkout -q -f -B kisskb 2d9cdedc4bdfec9a9d484d3564a1153c3f76ae2d
# git clean -qxdf
# < git log -1
# commit 2d9cdedc4bdfec9a9d484d3564a1153c3f76ae2d
# Author: Qian Cai <cai@redhat.com>
# Date:   Wed Oct 28 11:27:17 2020 -0400
# 
#     powerpc/eeh_cache: Fix a possible debugfs deadlock
#     
#     Lockdep complains that a possible deadlock below in
#     eeh_addr_cache_show() because it is acquiring a lock with IRQ enabled,
#     but eeh_addr_cache_insert_dev() needs to acquire the same lock with IRQ
#     disabled. Let's just make eeh_addr_cache_show() acquire the lock with
#     IRQ disabled as well.
#     
#             CPU0                    CPU1
#             ----                    ----
#        lock(&pci_io_addr_cache_root.piar_lock);
#                                     local_irq_disable();
#                                     lock(&tp->lock);
#                                     lock(&pci_io_addr_cache_root.piar_lock);
#        <Interrupt>
#          lock(&tp->lock);
#     
#       *** DEADLOCK ***
#     
#       lock_acquire+0x140/0x5f0
#       _raw_spin_lock_irqsave+0x64/0xb0
#       eeh_addr_cache_insert_dev+0x48/0x390
#       eeh_probe_device+0xb8/0x1a0
#       pnv_pcibios_bus_add_device+0x3c/0x80
#       pcibios_bus_add_device+0x118/0x290
#       pci_bus_add_device+0x28/0xe0
#       pci_bus_add_devices+0x54/0xb0
#       pcibios_init+0xc4/0x124
#       do_one_initcall+0xac/0x528
#       kernel_init_freeable+0x35c/0x3fc
#       kernel_init+0x24/0x148
#       ret_from_kernel_thread+0x5c/0x80
#     
#       lock_acquire+0x140/0x5f0
#       _raw_spin_lock+0x4c/0x70
#       eeh_addr_cache_show+0x38/0x110
#       seq_read+0x1a0/0x660
#       vfs_read+0xc8/0x1f0
#       ksys_read+0x74/0x130
#       system_call_exception+0xf8/0x1d0
#       system_call_common+0xe8/0x218
#     
#     Fixes: 5ca85ae6318d ("powerpc/eeh_cache: Add a way to dump the EEH address cache")
#     Signed-off-by: Qian Cai <cai@redhat.com>
#     Reviewed-by: Oliver O'Halloran <oohall@gmail.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20201028152717.8967-1-cai@redhat.com
# < /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 2d9cdedc4bdfec9a9d484d3564a1153c3f76ae2d
# < make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_40x_makalu_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-  40x/makalu_defconfig
# < make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_40x_makalu_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-fixes_40x_makalu_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-fixes_40x_makalu_defconfig_powerpc-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/powerpc64-linux/bin/powerpc64-linux-  
/kisskb/src/block/genhd.c: In function 'diskstats_show':
/kisskb/src/block/genhd.c:1659:1: warning: the frame size of 1160 bytes is larger than 1024 bytes [-Wframe-larger-than=]
 }
 ^
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_40x_makalu_defconfig_powerpc-gcc4.9
# Build took: 0:00:46.159027