user/sven/linux.git/kernel, branch v5.10.65

bpf: Fix possible out of bound write in narrow load handling

2021-09-15T07:50:43Z

[ Upstream commit d7af7e497f0308bc97809cc48b58e8e0f13887e1 ] Fix a verifier bug found by smatch static checker in [0]. This problem has never been seen in prod to my best knowledge. Fixing it still seems to be a good idea since it's hard to say for sure whether it's possible or not to have a scenario where a combination of convert_ctx_access() and a narrow load would lead to an out of bound write. When narrow load is handled, one or two new instructions are added to insn_buf array, but before it was only checked that cnt >= ARRAY_SIZE(insn_buf) And it's safe to add a new instruction to insn_buf[cnt++] only once. The second try will lead to out of bound write. And this is what can happen if `shift` is set. Fix it by making sure that if the BPF_RSH instruction has to be added in addition to BPF_AND then there is enough space for two more instructions in insn_buf. The full report [0] is below: kernel/bpf/verifier.c:12304 convert_ctx_accesses() warn: offset 'cnt' incremented past end of array kernel/bpf/verifier.c:12311 convert_ctx_accesses() warn: offset 'cnt' incremented past end of array kernel/bpf/verifier.c 12282 12283 insn->off = off & ~(size_default - 1); 12284 insn->code = BPF_LDX | BPF_MEM | size_code; 12285 } 12286 12287 target_size = 0; 12288 cnt = convert_ctx_access(type, insn, insn_buf, env->prog, 12289 &target_size); 12290 if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf) || ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Bounds check. 12291 (ctx_field_size && !target_size)) { 12292 verbose(env, "bpf verifier is misconfigured\n"); 12293 return -EINVAL; 12294 } 12295 12296 if (is_narrower_load && size < target_size) { 12297 u8 shift = bpf_ctx_narrow_access_offset( 12298 off, size, size_default) * 8; 12299 if (ctx_field_size <= 4) { 12300 if (shift) 12301 insn_buf[cnt++] = BPF_ALU32_IMM(BPF_RSH, ^^^^^ increment beyond end of array 12302 insn->dst_reg, 12303 shift); --> 12304 insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg, ^^^^^ out of bounds write 12305 (1 << size * 8) - 1); 12306 } else { 12307 if (shift) 12308 insn_buf[cnt++] = BPF_ALU64_IMM(BPF_RSH, 12309 insn->dst_reg, 12310 shift); 12311 insn_buf[cnt++] = BPF_ALU64_IMM(BPF_AND, insn->dst_reg, ^^^^^^^^^^^^^^^ Same. 12312 (1ULL << size * 8) - 1); 12313 } 12314 } 12315 12316 new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt); 12317 if (!new_prog) 12318 return -ENOMEM; 12319 12320 delta += cnt - 1; 12321 12322 /* keep walking new program and skip insns we just inserted */ 12323 env->prog = new_prog; 12324 insn = new_prog->insnsi + i + delta; 12325 } 12326 12327 return 0; 12328 } [0] https://lore.kernel.org/bpf/20210817050843.GA21456@kili/ v1->v2: - clarify that problem was only seen by static checker but not in prod; Fixes: 46f53a65d2de ("bpf: Allow narrow loads with offset > 0") Reported-by: Dan Carpenter Signed-off-by: Andrey Ignatov Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210820163935.1902398-1-rdna@fb.com Signed-off-by: Sasha Levin

locking/lockdep: Mark local_lock_t

2021-09-15T07:50:41Z

[ Upstream commit dfd5e3f5fe27bda91d5cc028c86ffbb7a0614489 ] The local_lock_t's are special, because they cannot form IRQ inversions, make sure we can tell them apart from the rest of the locks. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Sasha Levin

PM: cpu: Make notifier chain use a raw_spinlock_t

2021-09-15T07:50:40Z

[ Upstream commit b2f6662ac08d0e7c25574ce53623c71bdae9dd78 ] Invoking atomic_notifier_chain_notify() requires acquiring a spinlock_t, which can block under CONFIG_PREEMPT_RT. Notifications for members of the cpu_pm notification chain will be issued by the idle task, which can never block. Making *all* atomic_notifiers use a raw_spinlock is too big of a hammer, as only notifications issued by the idle task are problematic. Special-case cpu_pm_notifier_chain by kludging a raw_notifier and raw_spinlock_t together, matching the atomic_notifier behavior with a raw_spinlock_t. Fixes: 70d932985757 ("notifier: Fix broken error handling pattern") Signed-off-by: Valentin Schneider Acked-by: Sebastian Andrzej Siewior Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

cgroup/cpuset: Fix violation of cpuset locking rule

2021-09-15T07:50:38Z

[ Upstream commit 6ba34d3c73674e46d9e126e4f0cee79e5ef2481c ] The cpuset fields that manage partition root state do not strictly follow the cpuset locking rule that update to cpuset has to be done with both the callback_lock and cpuset_mutex held. This is now fixed by making sure that the locking rule is upheld. Fixes: 3881b86128d0 ("cpuset: Add an error state to cpuset.sched.partition") Fixes: 4b842da276a8 ("cpuset: Make CPU hotplug work with partition") Signed-off-by: Waiman Long Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin

cgroup/cpuset: Miscellaneous code cleanup

2021-09-15T07:50:38Z

[ Upstream commit 0f3adb8a1e5f36e792598c1d77a2cfac9c90a4f9 ] Use more descriptive variable names for update_prstate(), remove unnecessary code and fix some typos. There is no functional change. Signed-off-by: Waiman Long Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin

PM: EM: Increase energy calculation precision

2021-09-15T07:50:37Z

[ Upstream commit 7fcc17d0cb12938d2b3507973a6f93fc9ed2c7a1 ] The Energy Model (EM) provides useful information about device power in each performance state to other subsystems like: Energy Aware Scheduler (EAS). The energy calculation in EAS does arithmetic operation based on the EM em_cpu_energy(). Current implementation of that function uses em_perf_state::cost as a pre-computed cost coefficient equal to: cost = power * max_frequency / frequency. The 'power' is expressed in milli-Watts (or in abstract scale). There are corner cases when the EAS energy calculation for two Performance Domains (PDs) return the same value. The EAS compares these values to choose smaller one. It might happen that this values are equal due to rounding error. In such scenario, we need better resolution, e.g. 1000 times better. To provide this possibility increase the resolution in the em_perf_state::cost for 64-bit architectures. The cost of increasing resolution on 32-bit is pretty high (64-bit division) and is not justified since there are no new 32bit big.LITTLE EAS systems expected which would benefit from this higher resolution. This patch allows to avoid the rounding to milli-Watt errors, which might occur in EAS energy estimation for each PD. The rounding error is common for small tasks which have small utilization value. There are two places in the code where it makes a difference: 1. In the find_energy_efficient_cpu() where we are searching for best_delta. We might suffer there when two PDs return the same result, like in the example below. Scenario: Low utilized system e.g. ~200 sum_util for PD0 and ~220 for PD1. There are quite a few small tasks ~10-15 util. These tasks would suffer for the rounding error. These utilization values are typical when running games on Android. One of our partners has reported 5..10mA less battery drain when running with increased resolution. Some details: We have two PDs: PD0 (big) and PD1 (little) Let's compare w/o patch set ('old') and w/ patch set ('new') We are comparing energy w/ task and w/o task placed in the PDs a) 'old' w/o patch set, PD0 task_util = 13 cost = 480 sum_util_w/o_task = 215 sum_util_w_task = 228 scale_cpu = 1024 energy_w/o_task = 480 * 215 / 1024 = 100.78 => 100 energy_w_task = 480 * 228 / 1024 = 106.87 => 106 energy_diff = 106 - 100 = 6 (this is equal to 'old' PD1's energy_diff in 'c)') b) 'new' w/ patch set, PD0 task_util = 13 cost = 480 * 1000 = 480000 sum_util_w/o_task = 215 sum_util_w_task = 228 energy_w/o_task = 480000 * 215 / 1024 = 100781 energy_w_task = 480000 * 228 / 1024 = 106875 energy_diff = 106875 - 100781 = 6094 (this is not equal to 'new' PD1's energy_diff in 'd)') c) 'old' w/o patch set, PD1 task_util = 13 cost = 160 sum_util_w/o_task = 283 sum_util_w_task = 293 scale_cpu = 355 energy_w/o_task = 160 * 283 / 355 = 127.55 => 127 energy_w_task = 160 * 296 / 355 = 133.41 => 133 energy_diff = 133 - 127 = 6 (this is equal to 'old' PD0's energy_diff in 'a)') d) 'new' w/ patch set, PD1 task_util = 13 cost = 160 * 1000 = 160000 sum_util_w/o_task = 283 sum_util_w_task = 293 scale_cpu = 355 energy_w/o_task = 160000 * 283 / 355 = 127549 energy_w_task = 160000 * 296 / 355 = 133408 energy_diff = 133408 - 127549 = 5859 (this is not equal to 'new' PD0's energy_diff in 'b)') 2. Difference in the 6% energy margin filter at the end of find_energy_efficient_cpu(). With this patch the margin comparison also has better resolution, so it's possible to have better task placement thanks to that. Fixes: 27871f7a8a341ef ("PM: Introduce an Energy Model management framework") Reported-by: CCJ Yeh Reviewed-by: Dietmar Eggemann Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

cgroup/cpuset: Fix a partition bug with hotplug

2021-09-15T07:50:35Z

[ Upstream commit 15d428e6fe77fffc3f4fff923336036f5496ef17 ] In cpuset_hotplug_workfn(), the detection of whether the cpu list has been changed is done by comparing the effective cpus of the top cpuset with the cpu_active_mask. However, in the rare case that just all the CPUs in the subparts_cpus are offlined, the detection fails and the partition states are not updated correctly. Fix it by forcing the cpus_updated flag to true in this particular case. Fixes: 4b842da276a8 ("cpuset: Make CPU hotplug work with partition") Signed-off-by: Waiman Long Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin

bpf: Fix potential memleak and UAF in the verifier.

2021-09-15T07:50:31Z

[ Upstream commit 75f0fc7b48ad45a2e5736bcf8de26c8872fe8695 ] In bpf_patch_insn_data(), we first use the bpf_patch_insn_single() to insert new instructions, then use adjust_insn_aux_data() to adjust insn_aux_data. If the old env->prog have no enough room for new inserted instructions, we use bpf_prog_realloc to construct new_prog and free the old env->prog. There have two errors here. First, if adjust_insn_aux_data() return ENOMEM, we should free the new_prog. Second, if adjust_insn_aux_data() return ENOMEM, bpf_patch_insn_data() will return NULL, and env->prog has been freed in bpf_prog_realloc, but we will use it in bpf_check(). So in this patch, we make the adjust_insn_aux_data() never fails. In bpf_patch_insn_data(), we first pre-malloc memory for the new insn_aux_data, then call bpf_patch_insn_single() to insert new instructions, at last call adjust_insn_aux_data() to adjust insn_aux_data. Fixes: 8041902dae52 ("bpf: adjust insn_aux_data when patching insns") Signed-off-by: He Fengqing Signed-off-by: Alexei Starovoitov Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20210714101815.164322-1-hefengqing@huawei.com Signed-off-by: Sasha Levin

genirq/timings: Fix error return code in irq_timings_test_irqs()

2021-09-15T07:50:29Z

[ Upstream commit 290fdc4b7ef14e33d0e30058042b0e9bfd02b89b ] Return a negative error code from the error handling case instead of 0, as done elsewhere in this function. Fixes: f52da98d900e ("genirq/timings: Add selftest for irqs circular buffer") Reported-by: Hulk Robot Signed-off-by: Zhen Lei Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20210811093333.2376-1-thunder.leizhen@huawei.com Signed-off-by: Sasha Levin

rcu: Fix stall-warning deadlock due to non-release of rcu_node ->lock

2021-09-15T07:50:28Z

[ Upstream commit dc87740c8a6806bd2162bfb441770e4e53be5601 ] If rcu_print_task_stall() is invoked on an rcu_node structure that does not contain any tasks blocking the current grace period, it takes an early exit that fails to release that rcu_node structure's lock. This results in a self-deadlock, which is detected by lockdep. To reproduce this bug: tools/testing/selftests/rcutorture/bin/kvm.sh --allcpus --duration 3 --trust-make --configs "TREE03" --kconfig "CONFIG_PROVE_LOCKING=y" --bootargs "rcutorture.stall_cpu=30 rcutorture.stall_cpu_block=1 rcutorture.fwd_progress=0 rcutorture.test_boost=0" This will also result in other complaints, including RCU's scheduler hook complaining about blocking rather than preemption and an rcutorture writer stall. Only a partial RCU CPU stall warning message will be printed because of the self-deadlock. This commit therefore releases the lock on the rcu_print_task_stall() function's early exit path. Fixes: c583bcb8f5ed ("rcu: Don't invoke try_invoke_on_locked_down_task() with irqs disabled") Tested-by: Qais Yousef Signed-off-by: Yanfei Xu Signed-off-by: Paul E. McKenney Signed-off-by: Sasha Levin