* [PATCH] udf: shut up pointer cast warning
@ 2021-11-09 12:36 Arnd Bergmann
2021-11-10 11:00 ` Jan Kara
0 siblings, 1 reply; 3+ messages in thread
From: Arnd Bergmann @ 2021-11-09 12:36 UTC (permalink / raw)
To: Jan Kara; +Cc: Arnd Bergmann, linux-kernel
From: Arnd Bergmann <arnd@arndb.de>
On 32-bit architectures, the workaround of storing the directory position
in the private_data pointer causes a warning, as loff_t does not fit in
a pointer:
fs/udf/dir.c: In function 'udf_readdir':
fs/udf/dir.c:78:25: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
78 | if (ctx->pos != (uintptr_t)file->private_data) {
| ^
fs/udf/dir.c:211:30: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
211 | file->private_data = (void *)(uintptr_t)ctx->pos;
| ^
An extra cast to uintptr_t shuts up the warning. This is of course
still broken if the position is ever beyond the first 2^32 bytes (4GB).
I have not found a clear information on whether directories this
large are allowed on UDF, but it seems unlikely.
Fixes: 39a464de961f ("udf: Fix crash after seekdir")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
fs/udf/dir.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/udf/dir.c b/fs/udf/dir.c
index 8ae501d27eff..5aaa82be420a 100644
--- a/fs/udf/dir.c
+++ b/fs/udf/dir.c
@@ -75,7 +75,7 @@ static int udf_readdir(struct file *file, struct dir_context *ctx)
* identifying beginning of dir entry (names are under user control),
* we need to scan the directory from the beginning.
*/
- if (ctx->pos != (loff_t)file->private_data) {
+ if (ctx->pos != (uintptr_t)file->private_data) {
emit_pos = nf_pos;
nf_pos = 0;
}
@@ -208,7 +208,7 @@ static int udf_readdir(struct file *file, struct dir_context *ctx)
out:
/* Store position where we've ended */
- file->private_data = (void *)ctx->pos;
+ file->private_data = (void *)(uintptr_t)ctx->pos;
if (fibh.sbh != fibh.ebh)
brelse(fibh.ebh);
brelse(fibh.sbh);
--
2.29.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] udf: shut up pointer cast warning
2021-11-09 12:36 [PATCH] udf: shut up pointer cast warning Arnd Bergmann
@ 2021-11-10 11:00 ` Jan Kara
2021-11-10 11:22 ` Arnd Bergmann
0 siblings, 1 reply; 3+ messages in thread
From: Jan Kara @ 2021-11-10 11:00 UTC (permalink / raw)
To: Arnd Bergmann; +Cc: Jan Kara, Arnd Bergmann, linux-kernel
On Tue 09-11-21 13:36:08, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> On 32-bit architectures, the workaround of storing the directory position
> in the private_data pointer causes a warning, as loff_t does not fit in
> a pointer:
>
> fs/udf/dir.c: In function 'udf_readdir':
> fs/udf/dir.c:78:25: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
> 78 | if (ctx->pos != (uintptr_t)file->private_data) {
> | ^
> fs/udf/dir.c:211:30: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
> 211 | file->private_data = (void *)(uintptr_t)ctx->pos;
> | ^
>
> An extra cast to uintptr_t shuts up the warning. This is of course
> still broken if the position is ever beyond the first 2^32 bytes (4GB).
>
> I have not found a clear information on whether directories this
> large are allowed on UDF, but it seems unlikely.
>
> Fixes: 39a464de961f ("udf: Fix crash after seekdir")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Thanks Arnd but the problem was actually (mostly theoretical) problem on
32-bita archs and furthermore I've realized it didn't completely fix the
original problem either. Yesterday I've pushed a different fix to
linux-next. So the warning should disappear.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] udf: shut up pointer cast warning
2021-11-10 11:00 ` Jan Kara
@ 2021-11-10 11:22 ` Arnd Bergmann
0 siblings, 0 replies; 3+ messages in thread
From: Arnd Bergmann @ 2021-11-10 11:22 UTC (permalink / raw)
To: Jan Kara; +Cc: Jan Kara, Arnd Bergmann, Linux Kernel Mailing List
On Wed, Nov 10, 2021 at 12:00 PM Jan Kara <jack@suse.cz> wrote:
>
> Thanks Arnd but the problem was actually (mostly theoretical) problem on
> 32-bita archs and furthermore I've realized it didn't completely fix the
> original problem either. Yesterday I've pushed a different fix to
> linux-next. So the warning should disappear.
Yes, I saw your new patch and it is definitely a better fix.
Thanks,
Arnd
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-11-09 12:36 [PATCH] udf: shut up pointer cast warning Arnd Bergmann
2021-11-10 11:00 ` Jan Kara
2021-11-10 11:22 ` Arnd Bergmann
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