gpiolib: cdev: fix uninitialised kfifo
[ Upstream commitee0166b637
] If a line is requested with debounce, and that results in debouncing in software, and the line is subsequently reconfigured to enable edge detection then the allocation of the kfifo to contain edge events is overlooked. This results in events being written to and read from an uninitialised kfifo. Read events are returned to userspace. Initialise the kfifo in the case where the software debounce is already active. Fixes:65cff70464
("gpiolib: cdev: support setting debounce") Signed-off-by: Kent Gibson <warthog618@gmail.com> Link: https://lore.kernel.org/r/20240510065342.36191-1-warthog618@gmail.com Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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@ -1201,6 +1201,8 @@ static int edge_detector_update(struct line *line,
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struct gpio_v2_line_config *lc,
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unsigned int line_idx, u64 edflags)
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{
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u64 eflags;
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int ret;
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u64 active_edflags = READ_ONCE(line->edflags);
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unsigned int debounce_period_us =
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gpio_v2_line_config_debounce_period(lc, line_idx);
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@ -1212,6 +1214,18 @@ static int edge_detector_update(struct line *line,
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/* sw debounced and still will be...*/
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if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
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line_set_debounce_period(line, debounce_period_us);
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/*
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* ensure event fifo is initialised if edge detection
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* is now enabled.
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*/
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eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
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if (eflags && !kfifo_initialized(&line->req->events)) {
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ret = kfifo_alloc(&line->req->events,
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line->req->event_buffer_size,
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GFP_KERNEL);
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if (ret)
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return ret;
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}
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return 0;
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}
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