* [PATCH] i3c/master: Fix a potentially infinite loop in 'hci_dat_v1_get_index()'
@ 2021-11-17 22:05 Christophe JAILLET
2021-11-19 23:16 ` Nicolas Pitre
2021-12-10 15:39 ` Alexandre Belloni
0 siblings, 2 replies; 3+ messages in thread
From: Christophe JAILLET @ 2021-11-17 22:05 UTC (permalink / raw)
To: alexandre.belloni, npitre, boris.brezillon
Cc: linux-i3c, linux-kernel, kernel-janitors, Christophe JAILLET
The code in 'hci_dat_v1_get_index()' really looks like a hand coded version
of 'for_each_set_bit()', except that a +1 is missing when searching for the
next set bit.
This really looks odd and it seems that it will loop until 'dat_w0_read()'
returns the expected result.
So use 'for_each_set_bit()' instead. It is less verbose and should be more
correct.
Fixes: 9ad9a52cce28 ("i3c/master: introduce the mipi-i3c-hci driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
Speculative fix. Untested.
---
drivers/i3c/master/mipi-i3c-hci/dat_v1.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
index 783e551a2c85..97bb49ff5b53 100644
--- a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
+++ b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
@@ -160,9 +160,7 @@ static int hci_dat_v1_get_index(struct i3c_hci *hci, u8 dev_addr)
unsigned int dat_idx;
u32 dat_w0;
- for (dat_idx = find_first_bit(hci->DAT_data, hci->DAT_entries);
- dat_idx < hci->DAT_entries;
- dat_idx = find_next_bit(hci->DAT_data, hci->DAT_entries, dat_idx)) {
+ for_each_set_bit(dat_idx, hci->DAT_data, hci->DAT_entries) {
dat_w0 = dat_w0_read(dat_idx);
if (FIELD_GET(DAT_0_DYNAMIC_ADDRESS, dat_w0) == dev_addr)
return dat_idx;
--
2.30.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] i3c/master: Fix a potentially infinite loop in 'hci_dat_v1_get_index()'
2021-11-17 22:05 [PATCH] i3c/master: Fix a potentially infinite loop in 'hci_dat_v1_get_index()' Christophe JAILLET
@ 2021-11-19 23:16 ` Nicolas Pitre
2021-12-10 15:39 ` Alexandre Belloni
1 sibling, 0 replies; 3+ messages in thread
From: Nicolas Pitre @ 2021-11-19 23:16 UTC (permalink / raw)
To: Christophe JAILLET
Cc: alexandre.belloni, boris.brezillon, linux-i3c, linux-kernel,
kernel-janitors
On Wed, 17 Nov 2021, Christophe JAILLET wrote:
> The code in 'hci_dat_v1_get_index()' really looks like a hand coded version
> of 'for_each_set_bit()', except that a +1 is missing when searching for the
> next set bit.
>
> This really looks odd and it seems that it will loop until 'dat_w0_read()'
> returns the expected result.
>
> So use 'for_each_set_bit()' instead. It is less verbose and should be more
> correct.
>
> Fixes: 9ad9a52cce28 ("i3c/master: introduce the mipi-i3c-hci driver")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Nicolas Pitre <npitre@baylibre.com>
> ---
> Speculative fix. Untested.
> ---
> drivers/i3c/master/mipi-i3c-hci/dat_v1.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
> index 783e551a2c85..97bb49ff5b53 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
> @@ -160,9 +160,7 @@ static int hci_dat_v1_get_index(struct i3c_hci *hci, u8 dev_addr)
> unsigned int dat_idx;
> u32 dat_w0;
>
> - for (dat_idx = find_first_bit(hci->DAT_data, hci->DAT_entries);
> - dat_idx < hci->DAT_entries;
> - dat_idx = find_next_bit(hci->DAT_data, hci->DAT_entries, dat_idx)) {
> + for_each_set_bit(dat_idx, hci->DAT_data, hci->DAT_entries) {
> dat_w0 = dat_w0_read(dat_idx);
> if (FIELD_GET(DAT_0_DYNAMIC_ADDRESS, dat_w0) == dev_addr)
> return dat_idx;
> --
> 2.30.2
>
>
> --
> linux-i3c mailing list
> linux-i3c@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-i3c
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] i3c/master: Fix a potentially infinite loop in 'hci_dat_v1_get_index()'
2021-11-17 22:05 [PATCH] i3c/master: Fix a potentially infinite loop in 'hci_dat_v1_get_index()' Christophe JAILLET
2021-11-19 23:16 ` Nicolas Pitre
@ 2021-12-10 15:39 ` Alexandre Belloni
1 sibling, 0 replies; 3+ messages in thread
From: Alexandre Belloni @ 2021-12-10 15:39 UTC (permalink / raw)
To: boris.brezillon, Christophe JAILLET, npitre
Cc: Alexandre Belloni, linux-i3c, linux-kernel, kernel-janitors
On Wed, 17 Nov 2021 23:05:23 +0100, Christophe JAILLET wrote:
> The code in 'hci_dat_v1_get_index()' really looks like a hand coded version
> of 'for_each_set_bit()', except that a +1 is missing when searching for the
> next set bit.
>
> This really looks odd and it seems that it will loop until 'dat_w0_read()'
> returns the expected result.
>
> [...]
Applied, thanks!
[1/1] i3c/master: Fix a potentially infinite loop in 'hci_dat_v1_get_index()'
commit: 3f43926f271287fb1744c9ac9ae1122497f2b0c2
Best regards,
--
Alexandre Belloni <alexandre.belloni@bootlin.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-11-19 23:16 ` Nicolas Pitre
2021-12-10 15:39 ` Alexandre Belloni
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