# git rev-parse -q --verify 3bf9c3bd86cdde4aa4d12c2705d93e1d90464710^{commit}
3bf9c3bd86cdde4aa4d12c2705d93e1d90464710
already have revision, skipping fetch
# git checkout -q -f -B kisskb 3bf9c3bd86cdde4aa4d12c2705d93e1d90464710
# git clean -qxdf
# < git log -1
# commit 3bf9c3bd86cdde4aa4d12c2705d93e1d90464710
# Author: Frederic Barrat <fbarrat@linux.ibm.com>
# Date:   Mon Jun 24 16:41:48 2019 +0200
# 
#     ocxl: Fix concurrent AFU open and device removal
#     
#     If an ocxl device is unbound through sysfs at the same time its AFU is
#     being opened by a user process, the open code may dereference freed
#     stuctures, which can lead to kernel oops messages. You'd have to hit a
#     tiny time window, but it's possible. It's fairly easy to test by
#     making the time window bigger artificially.
#     
#     Fix it with a combination of 2 changes:
#       - when an AFU device is found in the IDR by looking for the device
#         minor number, we should hold a reference on the device until after
#         the context is allocated. A reference on the AFU structure is kept
#         when the context is allocated, so we can release the reference on
#         the device after the context allocation.
#       - with the fix above, there's still another even tinier window,
#         between the time the AFU device is found in the IDR and the
#         reference on the device is taken. We can fix this one by removing
#         the IDR entry earlier, when the device setup is removed, instead
#         of waiting for the 'release' device callback. With proper locking
#         around the IDR.
#     
#     Fixes: 75ca758adbaf ("ocxl: Create a clear delineation between ocxl backend & frontend")
#     Cc: stable@vger.kernel.org # v5.2+
#     Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
#     Reviewed-by: Greg Kurz <groug@kaod.org>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20190624144148.32022-1-fbarrat@linux.ibm.com
# < /opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux-gcc --version
# < /opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux-ld --version
# < git log --format=%s --max-count=1 3bf9c3bd86cdde4aa4d12c2705d93e1d90464710
# < make -s -j 80 ARCH=arm64 O=/kisskb/build/powerpc-fixes_arm64-defconfig_arm64-gcc5.4 CROSS_COMPILE=/opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux-  defconfig
# make -s -j 80 ARCH=arm64 O=/kisskb/build/powerpc-fixes_arm64-defconfig_arm64-gcc5.4 CROSS_COMPILE=/opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux-  
arch/arm64/Makefile:27: ld does not support --fix-cortex-a53-843419; kernel may be susceptible to erratum
arch/arm64/Makefile:38: LSE atomics not supported by binutils
/kisskb/src/drivers/i2c/busses/i2c-sh_mobile.c: In function 'sh_mobile_i2c_isr':
/kisskb/src/drivers/i2c/busses/i2c-sh_mobile.c:399:26: warning: 'data' may be used uninitialized in this function [-Wmaybe-uninitialized]
   pd->msg->buf[real_pos] = data;
                          ^
/kisskb/src/drivers/i2c/busses/i2c-sh_mobile.c:372:16: note: 'data' was declared here
  unsigned char data;
                ^
In file included from /kisskb/src/include/linux/rwsem.h:16:0,
                 from /kisskb/src/include/linux/notifier.h:15,
                 from /kisskb/src/include/linux/clk.h:14,
                 from /kisskb/src/drivers/tty/serial/sh-sci.c:24:
/kisskb/src/drivers/tty/serial/sh-sci.c: In function 'sci_dma_rx_submit':
/kisskb/src/include/linux/spinlock.h:288:3: warning: 'flags' may be used uninitialized in this function [-Wmaybe-uninitialized]
   _raw_spin_unlock_irqrestore(lock, flags); \
   ^
/kisskb/src/drivers/tty/serial/sh-sci.c:1352:16: note: 'flags' was declared here
  unsigned long flags;
                ^
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_arm64-defconfig_arm64-gcc5.4
# Build took: 0:04:48.318037