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/dim.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 88 insertions(+) create mode 100644 lib/dim/dim.c (limited to 'lib/dim/dim.c') diff --git a/lib/dim/dim.c b/lib/dim/dim.c new file mode 100644 index 000000000..97c3d084e --- /dev/null +++ b/lib/dim/dim.c @@ -0,0 +1,88 @@ +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB +/* + * Copyright (c) 2019, Mellanox Technologies inc. All rights reserved. + */ + +#include + +bool dim_on_top(struct dim *dim) +{ + switch (dim->tune_state) { + case DIM_PARKING_ON_TOP: + case DIM_PARKING_TIRED: + return true; + case DIM_GOING_RIGHT: + return (dim->steps_left > 1) && (dim->steps_right == 1); + default: /* DIM_GOING_LEFT */ + return (dim->steps_right > 1) && (dim->steps_left == 1); + } +} +EXPORT_SYMBOL(dim_on_top); + +void dim_turn(struct dim *dim) +{ + switch (dim->tune_state) { + case DIM_PARKING_ON_TOP: + case DIM_PARKING_TIRED: + break; + case DIM_GOING_RIGHT: + dim->tune_state = DIM_GOING_LEFT; + dim->steps_left = 0; + break; + case DIM_GOING_LEFT: + dim->tune_state = DIM_GOING_RIGHT; + dim->steps_right = 0; + break; + } +} +EXPORT_SYMBOL(dim_turn); + +void dim_park_on_top(struct dim *dim) +{ + dim->steps_right = 0; + dim->steps_left = 0; + dim->tired = 0; + dim->tune_state = DIM_PARKING_ON_TOP; +} +EXPORT_SYMBOL(dim_park_on_top); + +void dim_park_tired(struct dim *dim) +{ + dim->steps_right = 0; + dim->steps_left = 0; + dim->tune_state = DIM_PARKING_TIRED; +} +EXPORT_SYMBOL(dim_park_tired); + +bool dim_calc_stats(const struct dim_sample *start, + const struct dim_sample *end, + struct dim_stats *curr_stats) +{ + /* u32 holds up to 71 minutes, should be enough */ + u32 delta_us = ktime_us_delta(end->time, start->time); + u32 npkts = BIT_GAP(BITS_PER_TYPE(u32), end->pkt_ctr, start->pkt_ctr); + u32 nbytes = BIT_GAP(BITS_PER_TYPE(u32), end->byte_ctr, + start->byte_ctr); + u32 ncomps = BIT_GAP(BITS_PER_TYPE(u32), end->comp_ctr, + start->comp_ctr); + + if (!delta_us) + return false; + + curr_stats->ppms = DIV_ROUND_UP(npkts * USEC_PER_MSEC, delta_us); + curr_stats->bpms = DIV_ROUND_UP(nbytes * USEC_PER_MSEC, delta_us); + curr_stats->epms = DIV_ROUND_UP(DIM_NEVENTS * USEC_PER_MSEC, + delta_us); + curr_stats->cpms = DIV_ROUND_UP(ncomps * USEC_PER_MSEC, delta_us); + if (curr_stats->epms != 0) + curr_stats->cpe_ratio = DIV_ROUND_DOWN_ULL( + curr_stats->cpms * 100, curr_stats->epms); + else + curr_stats->cpe_ratio = 0; + + return true; +} +EXPORT_SYMBOL(dim_calc_stats); + +MODULE_DESCRIPTION("Dynamic Interrupt Moderation (DIM) library"); +MODULE_LICENSE("Dual BSD/GPL"); -- cgit v1.3.1