# git rev-parse -q --verify a5b9b743fdb653c37d347b303fb60dff0c743f7e^{commit} a5b9b743fdb653c37d347b303fb60dff0c743f7e already have revision, skipping fetch # git checkout -q -f -B kisskb a5b9b743fdb653c37d347b303fb60dff0c743f7e # git clean -qxdf # < git log -1 # commit a5b9b743fdb653c37d347b303fb60dff0c743f7e # Author: Frederic Barrat # 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 # Reviewed-by: Greg Kurz # Signed-off-by: Michael Ellerman # Link: https://lore.kernel.org/r/20190624144148.32022-1-fbarrat@linux.ibm.com # < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version # < git log --format=%s --max-count=1 a5b9b743fdb653c37d347b303fb60dff0c743f7e # < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_52xx_lite5200b_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- 52xx/lite5200b_defconfig # make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_52xx_lite5200b_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- /kisskb/src/arch/powerpc/platforms/52xx/lite5200_sleep.S: Assembler messages: /kisskb/src/arch/powerpc/platforms/52xx/lite5200_sleep.S:184: Warning: invalid register expression INFO: Uncompressed kernel (size 0x529b18) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x600000) INFO: Uncompressed kernel (size 0x529b18) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x600000) INFO: Uncompressed kernel (size 0x519460) overlaps the address of the wrapper(0x400000) INFO: Fixing the link_address of wrapper to (0x600000) Image Name: Linux-5.4.0-ga5b9b743fdb6 Created: Sat Dec 7 16:13:06 2019 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 2647179 Bytes = 2585.14 KiB = 2.52 MiB Load Address: 00600000 Entry Point: 00600284 Image Name: Linux-5.4.0-ga5b9b743fdb6 Created: Sat Dec 7 16:13:06 2019 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 2618189 Bytes = 2556.83 KiB = 2.50 MiB Load Address: 00000000 Entry Point: 00000000 Image Name: Linux-5.4.0-ga5b9b743fdb6 Created: Sat Dec 7 16:13:07 2019 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 2646734 Bytes = 2584.70 KiB = 2.52 MiB Load Address: 00600000 Entry Point: 00600284 Completed OK # rm -rf /kisskb/build/powerpc-fixes_52xx_lite5200b_defconfig_powerpc-gcc5 # Build took: 0:00:54.903527