Messages in this thread Patch in this message | | | From | Walter Harms <> | Subject | AW: [PATCH 2/2] tty: serial: samsung_tty: Fix a memory leak in s3c24xx_serial_getclk() when iterating clk | Date | Fri, 9 Jun 2023 08:57:14 +0000 |
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while we are here ....
perhaps INT_MAX from kernel.h ?
int deviation = (1 << 30) - 1;
the part before looks a bit strange
if (ourport->info->has_divslot) { unsigned long div = rate / req_baud;
/* The UDIVSLOT register on the newer UARTs allows us to * get a divisor adjustment of 1/16th on the baud clock. * * We don't keep the UDIVSLOT value (the 16ths we * calculated by not multiplying the baud by 16) as it * is easy enough to recalculate. */
quot = div / 16; baud = rate / div; because baud=rate/rate/req_baud = req_baud can this be simplyfied ? (or is the numeric required ?)
Homebrew abs() kernel.h has a abs() can we use it here ?
if (calc_deviation < 0) calc_deviation = -calc_deviation;
to the patch:
+ /* + * If we find a better clk, release the previous one, if + * any. + */ + if (!IS_ERR(*best_clk)) + clk_put(*best_clk);
the intentions are good. *best_clk is user supplied (and should be NULL) filled & released in the next round but IMHO must be valid (is clk). so no need to check. (ntl clk_put seems to handle NULL and ERR ) if (!clk || WARN_ON_ONCE(IS_ERR(clk))) return;
JM2C wh ________________________________________ Von: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Gesendet: Freitag, 9. Juni 2023 06:45:39 An: Krzysztof Kozlowski; Alim Akhtar; Greg Kroah-Hartman; Jiri Slaby; Thomas Abraham; Kukjin Kim Cc: linux-kernel@vger.kernel.org; kernel-janitors@vger.kernel.org; Christophe JAILLET; linux-arm-kernel@lists.infradead.org; linux-samsung-soc@vger.kernel.org; linux-serial@vger.kernel.org Betreff: [PATCH 2/2] tty: serial: samsung_tty: Fix a memory leak in s3c24xx_serial_getclk() when iterating clk
When the best clk is searched, we iterate over all possible clk.
If we find a better match, the previous one, if any, needs to be freed. If a better match has already been found, we still need to free the new one, otherwise it leaks.
Fixes: 5f5a7a5578c5 ("serial: samsung: switch to clkdev based clock lookup") Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> --- This patch is speculative. Review with care.
I think that some clk_put() are also missing somewhere else in the driver but won't be able to investigate further. --- drivers/tty/serial/samsung_tty.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c index dd751e7010e3..c07877dd25fa 100644 --- a/drivers/tty/serial/samsung_tty.c +++ b/drivers/tty/serial/samsung_tty.c @@ -1488,10 +1488,18 @@ static unsigned int s3c24xx_serial_getclk(struct s3c24xx_uart_port *ourport, calc_deviation = -calc_deviation;
if (calc_deviation < deviation) { + /* + * If we find a better clk, release the previous one, if + * any. + */ + if (!IS_ERR(*best_clk)) + clk_put(*best_clk); *best_clk = clk; best_quot = quot; *clk_num = cnt; deviation = calc_deviation; + } else { + clk_put(clk); } }
-- 2.34.1
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