# 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-8.1.0-nolibc/s390-linux/bin/s390-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/s390-linux/bin/s390-linux-ld --version # < git log --format=%s --max-count=1 a4d63c3732f1a0c91abcf5b7f32b4ef7dcd82025 # < make -s -j 48 ARCH=s390 O=/kisskb/build/linus_s390-allyesconfig_s390x-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/s390-linux/bin/s390-linux- allyesconfig # Added to kconfig CONFIG_BUILD_DOCSRC=n # Added to kconfig CONFIG_MODULE_SIG=n # < make -s -j 48 ARCH=s390 O=/kisskb/build/linus_s390-allyesconfig_s390x-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/s390-linux/bin/s390-linux- help # make -s -j 48 ARCH=s390 O=/kisskb/build/linus_s390-allyesconfig_s390x-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/s390-linux/bin/s390-linux- olddefconfig # make -s -j 48 ARCH=s390 O=/kisskb/build/linus_s390-allyesconfig_s390x-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/s390-linux/bin/s390-linux- /kisskb/src/drivers/input/joystick/analog.c:160:2: warning: #warning Precise timer not defined for this architecture. [-Wcpp] #warning Precise timer not defined for this architecture. ^~~~~~~ /kisskb/src/drivers/gpu/drm/rockchip/cdn-dp-core.c:1124:12: warning: 'cdn_dp_resume' defined but not used [-Wunused-function] static int cdn_dp_resume(struct device *dev) ^~~~~~~~~~~~~ /kisskb/src/drivers/staging/media/tegra-vde/vde.c:916:12: warning: 'tegra_vde_runtime_suspend' defined but not used [-Wunused-function] static int tegra_vde_runtime_suspend(struct device *dev) ^~~~~~~~~~~~~~~~~~~~~~~~~ In file included from /kisskb/src/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c:41: /kisskb/src/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c: In function 'mvpp2_setup_bm_pool': /kisskb/src/drivers/net/ethernet/marvell/mvpp2/mvpp2.h:647:2: warning: overflow in conversion from 'long unsigned int' to 'int' changes value from '18446744073709551584' to '-32' [-Woverflow] ((total_size) - MVPP2_SKB_HEADROOM - MVPP2_SKB_SHINFO_SIZE) ^ /kisskb/src/drivers/net/ethernet/marvell/mvpp2/mvpp2.h:714:33: note: in expansion of macro 'MVPP2_RX_MAX_PKT_SIZE' #define MVPP2_BM_SHORT_PKT_SIZE MVPP2_RX_MAX_PKT_SIZE(MVPP2_BM_SHORT_FRAME_SIZE) ^~~~~~~~~~~~~~~~~~~~~ /kisskb/src/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c:652:41: note: in expansion of macro 'MVPP2_BM_SHORT_PKT_SIZE' mvpp2_pools[MVPP2_BM_SHORT].pkt_size = MVPP2_BM_SHORT_PKT_SIZE; ^~~~~~~~~~~~~~~~~~~~~~~ Completed OK # rm -rf /kisskb/build/linus_s390-allyesconfig_s390x-gcc8 # Build took: 0:17:53.882120