# git rev-parse -q --verify ed16e99272308afe183d983523bf995e8a517026^{commit}
ed16e99272308afe183d983523bf995e8a517026
already have revision, skipping fetch
# git checkout -q -f -B kisskb ed16e99272308afe183d983523bf995e8a517026
# git clean -qxdf
# < git log -1
# commit ed16e99272308afe183d983523bf995e8a517026
# Author: Michael Neuling <mikey@neuling.org>
# Date:   Mon Mar 26 15:17:07 2018 +1100
# 
#     powerpc/eeh: Fix race with driver un/bind
#     
#     The current EEH callbacks can race with a driver unbind. This can
#     result in a backtraces like this:
#     
#       EEH: Frozen PHB#0-PE#1fc detected
#       EEH: PE location: S000009, PHB location: N/A
#       CPU: 2 PID: 2312 Comm: kworker/u258:3 Not tainted 4.15.6-openpower1 #2
#       Workqueue: nvme-wq nvme_reset_work [nvme]
#       Call Trace:
#         dump_stack+0x9c/0xd0 (unreliable)
#         eeh_dev_check_failure+0x420/0x470
#         eeh_check_failure+0xa0/0xa4
#         nvme_reset_work+0x138/0x1414 [nvme]
#         process_one_work+0x1ec/0x328
#         worker_thread+0x2e4/0x3a8
#         kthread+0x14c/0x154
#         ret_from_kernel_thread+0x5c/0xc8
#       nvme nvme1: Removing after probe failure status: -19
#       <snip>
#       cpu 0x23: Vector: 300 (Data Access) at [c000000ff50f3800]
#           pc: c0080000089a0eb0: nvme_error_detected+0x4c/0x90 [nvme]
#           lr: c000000000026564: eeh_report_error+0xe0/0x110
#           sp: c000000ff50f3a80
#          msr: 9000000000009033
#          dar: 400
#        dsisr: 40000000
#         current = 0xc000000ff507c000
#         paca    = 0xc00000000fdc9d80   softe: 0        irq_happened: 0x01
#           pid   = 782, comm = eehd
#       Linux version 4.15.6-openpower1 (smc@smc-desktop) (gcc version 6.4.0 (Buildroot 2017.11.2-00008-g4b6188e)) #2 SM                                             P Tue Feb 27 12:33:27 PST 2018
#       enter ? for help
#         eeh_report_error+0xe0/0x110
#         eeh_pe_dev_traverse+0xc0/0xdc
#         eeh_handle_normal_event+0x184/0x4c4
#         eeh_handle_event+0x30/0x288
#         eeh_event_handler+0x124/0x170
#         kthread+0x14c/0x154
#         ret_from_kernel_thread+0x5c/0xc8
#     
#     The first part is an EEH (on boot), the second half is the resulting
#     crash. nvme probe starts the nvme_reset_work() worker thread. This
#     worker thread starts touching the device which see a device error
#     (EEH) and hence queues up an event in the powerpc EEH worker
#     thread. nvme_reset_work() then continues and runs
#     nvme_remove_dead_ctrl_work() which results in unbinding the driver
#     from the device and hence releases all resources. At the same time,
#     the EEH worker thread starts doing the EEH .error_detected() driver
#     callback, which no longer works since the resources have been freed.
#     
#     This fixes the problem in the same way the generic PCIe AER code (in
#     drivers/pci/pcie/aer/aerdrv_core.c) does. It makes the EEH code hold
#     the device_lock() while performing the driver EEH callbacks and
#     associated code. This ensures either the callbacks are no longer
#     register, or if they are registered the driver will not be removed
#     from underneath us.
#     
#     This has been broken forever. The EEH call backs were first introduced
#     in 2005 (in 77bd7415610) but it's not clear if a lock was needed back
#     then.
#     
#     Fixes: 77bd74156101 ("[PATCH] powerpc: PCI Error Recovery: PPC64 core recovery routines")
#     Cc: stable@vger.kernel.org # v2.6.16+
#     Signed-off-by: Michael Neuling <mikey@neuling.org>
#     Reviewed-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-gcc --version
# < git log --format=%s --max-count=1 ed16e99272308afe183d983523bf995e8a517026
# < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_44x_akebono_defconfig_powerpc CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  44x/akebono_defconfig
# make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-next_44x_akebono_defconfig_powerpc CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/powerpc-linux/bin/powerpc-linux-  
/kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl':
/kisskb/src/kernel/printk/printk.c:183:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/rcu/srcutree.c: In function 'init_srcu_struct_fields':
/kisskb/src/kernel/rcu/srcutree.c:146:32: warning: 'levelspread[<U7e60>]' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/rcu/srcutree.c:94:6: note: 'levelspread[<U7e60>]' was declared here
/kisskb/src/drivers/tty/serial/8250/8250_core.c: In function 'univ8250_release_irq':
/kisskb/src/drivers/tty/serial/8250/8250_core.c:251:18: warning: 'i' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/tty/serial/8250/8250_core.c:231:19: note: 'i' was declared here
WARNING: modpost: Found 1 section mismatch(es).
To see full details build your kernel with:
'make CONFIG_DEBUG_SECTION_MISMATCH=y'
Completed OK
# rm -rf /kisskb/build/powerpc-next_44x_akebono_defconfig_powerpc
# Build took: 0:00:45.667813