From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- lib/dim/rdma_dim.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 109 insertions(+) create mode 100644 lib/dim/rdma_dim.c (limited to 'lib/dim/rdma_dim.c') diff --git a/lib/dim/rdma_dim.c b/lib/dim/rdma_dim.c new file mode 100644 index 000000000..88f779486 --- /dev/null +++ b/lib/dim/rdma_dim.c @@ -0,0 +1,109 @@ +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB +/* + * Copyright (c) 2019, Mellanox Technologies inc. All rights reserved. + */ + +#include + +static int rdma_dim_step(struct dim *dim) +{ + if (dim->tune_state == DIM_GOING_RIGHT) { + if (dim->profile_ix == (RDMA_DIM_PARAMS_NUM_PROFILES - 1)) + return DIM_ON_EDGE; + dim->profile_ix++; + dim->steps_right++; + } + if (dim->tune_state == DIM_GOING_LEFT) { + if (dim->profile_ix == 0) + return DIM_ON_EDGE; + dim->profile_ix--; + dim->steps_left++; + } + + return DIM_STEPPED; +} + +static int rdma_dim_stats_compare(struct dim_stats *curr, + struct dim_stats *prev) +{ + /* first stat */ + if (!prev->cpms) + return DIM_STATS_SAME; + + if (IS_SIGNIFICANT_DIFF(curr->cpms, prev->cpms)) + return (curr->cpms > prev->cpms) ? DIM_STATS_BETTER : + DIM_STATS_WORSE; + + if (IS_SIGNIFICANT_DIFF(curr->cpe_ratio, prev->cpe_ratio)) + return (curr->cpe_ratio > prev->cpe_ratio) ? DIM_STATS_BETTER : + DIM_STATS_WORSE; + + return DIM_STATS_SAME; +} + +static bool rdma_dim_decision(struct dim_stats *curr_stats, struct dim *dim) +{ + int prev_ix = dim->profile_ix; + u8 state = dim->tune_state; + int stats_res; + int step_res; + + if (state != DIM_PARKING_ON_TOP && state != DIM_PARKING_TIRED) { + stats_res = rdma_dim_stats_compare(curr_stats, + &dim->prev_stats); + + switch (stats_res) { + case DIM_STATS_SAME: + if (curr_stats->cpe_ratio <= 50 * prev_ix) + dim->profile_ix = 0; + break; + case DIM_STATS_WORSE: + dim_turn(dim); + fallthrough; + case DIM_STATS_BETTER: + step_res = rdma_dim_step(dim); + if (step_res == DIM_ON_EDGE) + dim_turn(dim); + break; + } + } + + dim->prev_stats = *curr_stats; + + return dim->profile_ix != prev_ix; +} + +void rdma_dim(struct dim *dim, u64 completions) +{ + struct dim_sample *curr_sample = &dim->measuring_sample; + struct dim_stats curr_stats; + u32 nevents; + + dim_update_sample_with_comps(curr_sample->event_ctr + 1, 0, 0, + curr_sample->comp_ctr + completions, + &dim->measuring_sample); + + switch (dim->state) { + case DIM_MEASURE_IN_PROGRESS: + nevents = curr_sample->event_ctr - dim->start_sample.event_ctr; + if (nevents < DIM_NEVENTS) + break; + if (!dim_calc_stats(&dim->start_sample, curr_sample, &curr_stats)) + break; + if (rdma_dim_decision(&curr_stats, dim)) { + dim->state = DIM_APPLY_NEW_PROFILE; + schedule_work(&dim->work); + break; + } + fallthrough; + case DIM_START_MEASURE: + dim->state = DIM_MEASURE_IN_PROGRESS; + dim_update_sample_with_comps(curr_sample->event_ctr, 0, 0, + curr_sample->comp_ctr, + &dim->start_sample); + break; + case DIM_APPLY_NEW_PROFILE: + break; + } +} +EXPORT_SYMBOL(rdma_dim); -- cgit v1.3.1