# git rev-parse -q --verify a4d63c3732f1a0c91abcf5b7f32b4ef7dcd82025^{commit} a4d63c3732f1a0c91abcf5b7f32b4ef7dcd82025 already have revision, skipping fetch # git checkout -q -f -B kisskb a4d63c3732f1a0c91abcf5b7f32b4ef7dcd82025 # git clean -qxdf # < git log -1 # commit a4d63c3732f1a0c91abcf5b7f32b4ef7dcd82025 # Author: Jason A. Donenfeld # Date: Mon Sep 28 12:35:07 2020 +0200 # # mm: do not rely on mm == current->mm in __get_user_pages_locked # # It seems likely this block was pasted from internal_get_user_pages_fast, # which is not passed an mm struct and therefore uses current's. But # __get_user_pages_locked is passed an explicit mm, and current->mm is not # always valid. This was hit when being called from i915, which uses: # # pin_user_pages_remote-> # __get_user_pages_remote-> # __gup_longterm_locked-> # __get_user_pages_locked # # Before, this would lead to an OOPS: # # BUG: kernel NULL pointer dereference, address: 0000000000000064 # #PF: supervisor write access in kernel mode # #PF: error_code(0x0002) - not-present page # CPU: 10 PID: 1431 Comm: kworker/u33:1 Tainted: P S U O 5.9.0-rc7+ #140 # Hardware name: LENOVO 20QTCTO1WW/20QTCTO1WW, BIOS N2OET47W (1.34 ) 08/06/2020 # Workqueue: i915-userptr-acquire __i915_gem_userptr_get_pages_worker [i915] # RIP: 0010:__get_user_pages_remote+0xd7/0x310 # Call Trace: # __i915_gem_userptr_get_pages_worker+0xc8/0x260 [i915] # process_one_work+0x1ca/0x390 # worker_thread+0x48/0x3c0 # kthread+0x114/0x130 # ret_from_fork+0x1f/0x30 # CR2: 0000000000000064 # # This commit fixes the problem by using the mm pointer passed to the # function rather than the bogus one in current. # # Fixes: 008cfe4418b3 ("mm: Introduce mm_struct.has_pinned") # Tested-by: Chris Wilson # Reported-by: Harald Arnesen # Reviewed-by: Jason Gunthorpe # Reviewed-by: Peter Xu # Signed-off-by: Jason A. Donenfeld # Signed-off-by: Linus Torvalds # < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi-gcc --version # < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi-ld --version # < git log --format=%s --max-count=1 a4d63c3732f1a0c91abcf5b7f32b4ef7dcd82025 # < make -s -j 48 ARCH=arm O=/kisskb/build/linus_rpc_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- rpc_defconfig # < make -s -j 48 ARCH=arm O=/kisskb/build/linus_rpc_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- help # make -s -j 48 ARCH=arm O=/kisskb/build/linus_rpc_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- olddefconfig # make -s -j 48 ARCH=arm O=/kisskb/build/linus_rpc_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- /kisskb/src/drivers/tty/vt/vt_ioctl.c: In function 'vt_ioctl': /kisskb/src/drivers/tty/vt/vt_ioctl.c:1058:1: internal compiler error: Max. number of generated reload insns per insn is achieved (90) } ^ Please submit a full bug report, with preprocessed source if appropriate. See for instructions. make[4]: *** [/kisskb/src/scripts/Makefile.build:283: drivers/tty/vt/vt_ioctl.o] Error 1 make[4]: *** Waiting for unfinished jobs.... make[3]: *** [/kisskb/src/scripts/Makefile.build:500: drivers/tty/vt] Error 2 make[3]: *** Waiting for unfinished jobs.... make[2]: *** [/kisskb/src/scripts/Makefile.build:500: drivers/tty] Error 2 make[2]: *** Waiting for unfinished jobs.... /kisskb/src/fs/fat/dir.c: In function 'fat_ioctl_filldir': /kisskb/src/fs/fat/dir.c:759:43: internal compiler error: Max. number of generated reload insns per insn is achieved (90) FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent) ^ /kisskb/src/fs/fat/dir.c:714:9: note: in definition of macro 'FAT_IOCTL_FILLDIR_FUNC' struct dirent_type __user *d2 = d1 + 1; \ ^ Please submit a full bug report, with preprocessed source if appropriate. See for instructions. make[3]: *** [/kisskb/src/scripts/Makefile.build:283: fs/fat/dir.o] Error 1 make[3]: *** Waiting for unfinished jobs.... make[2]: *** [/kisskb/src/scripts/Makefile.build:500: fs/fat] Error 2 make[2]: *** Waiting for unfinished jobs.... make[1]: *** [/kisskb/src/Makefile:1784: drivers] Error 2 make[1]: *** Waiting for unfinished jobs.... make[1]: *** [/kisskb/src/Makefile:1784: fs] Error 2 make: *** [Makefile:185: __sub-make] Error 2 Command 'make -s -j 48 ARCH=arm O=/kisskb/build/linus_rpc_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- ' returned non-zero exit status 2 # rm -rf /kisskb/build/linus_rpc_defconfig_arm-gcc4.9 # Build took: 0:00:39.043347