Re: pgsql: Fix potential stack overflow in incremental backup.

2024-04-10 Thread Thomas Munro
On Thu, Apr 11, 2024 at 2:28 PM Michael Paquier  wrote:
> + * file just as if this were not an incremental backup.  The contents of the
> + * relative_block_numbers array is unspecified in this case.
>
> Perhaps you mean s/is/are/ here?  The contents are what's not
> specified.

Thanks, fixed.  Duh.




Re: pgsql: Fix potential stack overflow in incremental backup.

2024-04-10 Thread Michael Paquier
Hi Thomas,

On Thu, Apr 11, 2024 at 01:53:24AM +, Thomas Munro wrote:
> Fix potential stack overflow in incremental backup.
> 
> The user can set RELSEG_SIZE to a high number at compile time, so we
> can't use it to control the size of an array on the stack: it could be
> many gigabytes in size.  On closer inspection, we don't really need that
> intermediate array anyway.  Let's just write directly into the output
> array, and then perform the absolute->relative adjustment in place.
> This fixes new code from commit dc212340058.

+ * file just as if this were not an incremental backup.  The contents of the
+ * relative_block_numbers array is unspecified in this case. 

Perhaps you mean s/is/are/ here?  The contents are what's not
specified.
--
Michael


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pgsql: Fix potential stack overflow in incremental backup.

2024-04-10 Thread Thomas Munro
Fix potential stack overflow in incremental backup.

The user can set RELSEG_SIZE to a high number at compile time, so we
can't use it to control the size of an array on the stack: it could be
many gigabytes in size.  On closer inspection, we don't really need that
intermediate array anyway.  Let's just write directly into the output
array, and then perform the absolute->relative adjustment in place.
This fixes new code from commit dc212340058.

Reviewed-by: Robert Haas 
Discussion: 
https://postgr.es/m/CA%2BhUKG%2B2hZ0sBztPW4mkLfng0qfkNtAHFUfxOMLizJ0BPmi5%2Bg%40mail.gmail.com

Branch
--
master

Details
---
https://git.postgresql.org/pg/commitdiff/d8f5acbdb9b22106db583e3cbb177d34e6b18eeb

Modified Files
--
src/backend/backup/basebackup_incremental.c | 26 +-
1 file changed, 17 insertions(+), 9 deletions(-)