tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 887a333c44eb67973622e530e43cd5e4cf9af927 commit: 367c9b0f1b8750a704070e7ae85234d591290434 [2083/2969] drm/amdkfd: Ensure mm remain valid in svm deferred_list work config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20220131/202201312316.DZLM8JSq-lkp@xxxxxxxxx/config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 2cdbaca3943a4d6259119f185656328bd3805b68) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=367c9b0f1b8750a704070e7ae85234d591290434 git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout 367c9b0f1b8750a704070e7ae85234d591290434 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/gpu/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@xxxxxxxxx> All warnings (new ones prefixed by >>): >> drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_svm.c:2067:22: warning: variable 'p' set but not used [-Wunused-but-set-variable] struct kfd_process *p; ^ 1 warning generated. vim +/p +2067 drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_svm.c 373e3ccd859b4b Philip Yang 2021-04-19 2061 4683cfecadeb38 Philip Yang 2020-04-08 2062 static void svm_range_deferred_list_work(struct work_struct *work) 4683cfecadeb38 Philip Yang 2020-04-08 2063 { 4683cfecadeb38 Philip Yang 2020-04-08 2064 struct svm_range_list *svms; 4683cfecadeb38 Philip Yang 2020-04-08 2065 struct svm_range *prange; 4683cfecadeb38 Philip Yang 2020-04-08 2066 struct mm_struct *mm; a0c55ecee10055 Philip Yang 2021-11-16 @2067 struct kfd_process *p; 4683cfecadeb38 Philip Yang 2020-04-08 2068 4683cfecadeb38 Philip Yang 2020-04-08 2069 svms = container_of(work, struct svm_range_list, deferred_list_work); 4683cfecadeb38 Philip Yang 2020-04-08 2070 pr_debug("enter svms 0x%p\n", svms); 4683cfecadeb38 Philip Yang 2020-04-08 2071 a0c55ecee10055 Philip Yang 2021-11-16 2072 p = container_of(svms, struct kfd_process, svms); 367c9b0f1b8750 Philip Yang 2022-01-18 2073 367c9b0f1b8750 Philip Yang 2022-01-18 2074 spin_lock(&svms->deferred_list_lock); 367c9b0f1b8750 Philip Yang 2022-01-18 2075 while (!list_empty(&svms->deferred_range_list)) { 367c9b0f1b8750 Philip Yang 2022-01-18 2076 prange = list_first_entry(&svms->deferred_range_list, 367c9b0f1b8750 Philip Yang 2022-01-18 2077 struct svm_range, deferred_list); 367c9b0f1b8750 Philip Yang 2022-01-18 2078 spin_unlock(&svms->deferred_list_lock); 367c9b0f1b8750 Philip Yang 2022-01-18 2079 367c9b0f1b8750 Philip Yang 2022-01-18 2080 pr_debug("prange 0x%p [0x%lx 0x%lx] op %d\n", prange, 367c9b0f1b8750 Philip Yang 2022-01-18 2081 prange->start, prange->last, prange->work_item.op); 367c9b0f1b8750 Philip Yang 2022-01-18 2082 367c9b0f1b8750 Philip Yang 2022-01-18 2083 mm = prange->work_item.mm; a44fe9ee051aca Felix Kuehling 2021-11-05 2084 retry: 4683cfecadeb38 Philip Yang 2020-04-08 2085 mmap_write_lock(mm); 4683cfecadeb38 Philip Yang 2020-04-08 2086 a0c55ecee10055 Philip Yang 2021-11-16 2087 /* Checking for the need to drain retry faults must be inside a44fe9ee051aca Felix Kuehling 2021-11-05 2088 * mmap write lock to serialize with munmap notifiers. 4683cfecadeb38 Philip Yang 2020-04-08 2089 */ 2e4477282c8cff Philip Yang 2021-11-19 2090 if (unlikely(atomic_read(&svms->drain_pagefaults))) { a44fe9ee051aca Felix Kuehling 2021-11-05 2091 mmap_write_unlock(mm); a44fe9ee051aca Felix Kuehling 2021-11-05 2092 svm_range_drain_retry_fault(svms); a44fe9ee051aca Felix Kuehling 2021-11-05 2093 goto retry; a44fe9ee051aca Felix Kuehling 2021-11-05 2094 } a0c55ecee10055 Philip Yang 2021-11-16 2095 367c9b0f1b8750 Philip Yang 2022-01-18 2096 /* Remove from deferred_list must be inside mmap write lock, for 367c9b0f1b8750 Philip Yang 2022-01-18 2097 * two race cases: 367c9b0f1b8750 Philip Yang 2022-01-18 2098 * 1. unmap_from_cpu may change work_item.op and add the range 367c9b0f1b8750 Philip Yang 2022-01-18 2099 * to deferred_list again, cause use after free bug. 367c9b0f1b8750 Philip Yang 2022-01-18 2100 * 2. svm_range_list_lock_and_flush_work may hold mmap write 367c9b0f1b8750 Philip Yang 2022-01-18 2101 * lock and continue because deferred_list is empty, but 367c9b0f1b8750 Philip Yang 2022-01-18 2102 * deferred_list work is actually waiting for mmap lock. 367c9b0f1b8750 Philip Yang 2022-01-18 2103 */ a0c55ecee10055 Philip Yang 2021-11-16 2104 spin_lock(&svms->deferred_list_lock); 4683cfecadeb38 Philip Yang 2020-04-08 2105 list_del_init(&prange->deferred_list); 4683cfecadeb38 Philip Yang 2020-04-08 2106 spin_unlock(&svms->deferred_list_lock); 4683cfecadeb38 Philip Yang 2020-04-08 2107 a0c55ecee10055 Philip Yang 2021-11-16 2108 mutex_lock(&svms->lock); 0b0e518d61af8e Felix Kuehling 2021-02-24 2109 mutex_lock(&prange->migrate_mutex); 4683cfecadeb38 Philip Yang 2020-04-08 2110 while (!list_empty(&prange->child_list)) { 4683cfecadeb38 Philip Yang 2020-04-08 2111 struct svm_range *pchild; 4683cfecadeb38 Philip Yang 2020-04-08 2112 4683cfecadeb38 Philip Yang 2020-04-08 2113 pchild = list_first_entry(&prange->child_list, 4683cfecadeb38 Philip Yang 2020-04-08 2114 struct svm_range, child_list); 4683cfecadeb38 Philip Yang 2020-04-08 2115 pr_debug("child prange 0x%p op %d\n", pchild, 4683cfecadeb38 Philip Yang 2020-04-08 2116 pchild->work_item.op); 4683cfecadeb38 Philip Yang 2020-04-08 2117 list_del_init(&pchild->child_list); 367c9b0f1b8750 Philip Yang 2022-01-18 2118 svm_range_handle_list_op(svms, pchild, mm); 4683cfecadeb38 Philip Yang 2020-04-08 2119 } 0b0e518d61af8e Felix Kuehling 2021-02-24 2120 mutex_unlock(&prange->migrate_mutex); 4683cfecadeb38 Philip Yang 2020-04-08 2121 367c9b0f1b8750 Philip Yang 2022-01-18 2122 svm_range_handle_list_op(svms, prange, mm); 4683cfecadeb38 Philip Yang 2020-04-08 2123 mutex_unlock(&svms->lock); 367c9b0f1b8750 Philip Yang 2022-01-18 2124 mmap_write_unlock(mm); 367c9b0f1b8750 Philip Yang 2022-01-18 2125 367c9b0f1b8750 Philip Yang 2022-01-18 2126 /* Pairs with mmget in svm_range_add_list_work */ 367c9b0f1b8750 Philip Yang 2022-01-18 2127 mmput(mm); 4683cfecadeb38 Philip Yang 2020-04-08 2128 4683cfecadeb38 Philip Yang 2020-04-08 2129 spin_lock(&svms->deferred_list_lock); 4683cfecadeb38 Philip Yang 2020-04-08 2130 } 4683cfecadeb38 Philip Yang 2020-04-08 2131 spin_unlock(&svms->deferred_list_lock); 4683cfecadeb38 Philip Yang 2020-04-08 2132 pr_debug("exit svms 0x%p\n", svms); 4683cfecadeb38 Philip Yang 2020-04-08 2133 } 4683cfecadeb38 Philip Yang 2020-04-08 2134 :::::: The code at line 2067 was first introduced by commit :::::: a0c55ecee10055901c9c1b46d0d129cb6b51fa5d drm/amdkfd: process exit and retry fault race :::::: TO: Philip Yang <Philip.Yang@xxxxxxx> :::::: CC: Alex Deucher <alexander.deucher@xxxxxxx> --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
