Re: [PATCH] configfs: avoid committing failed binary attribute writes

[Breno Leitao]

On Fri, Aug 21, 2026 at 03:33:41PM +0800, Yichong Chen wrote:
> Configfs binary attributes buffer write data and submit the final buffer
> on release.  The write path sets write_in_progress before it knows
> whether the current write can be accepted.
> 
> If the first write fails before any data is copied, for example because
> the write exceeds cb_max_size or the buffer allocation fails, release still
> treats the file as having a pending binary write and calls the attribute
> write callback with the current buffer state.  For ACPI configfs, an
> oversized first write to the aml attribute can therefore fail with -EFBIG
> and then oops on close when acpi_table_aml_write() is called with a NULL
> buffer.
> 
> Only mark the binary attribute as having a write in progress after data
> has actually been copied into the buffer.
> 
> Fixes: 03607ace807b ("configfs: implement binary attributes")
> Signed-off-by: Yichong Chen <chenyichong@xxxxxxxxxxxxx>

Reviewed-by: Breno Leitao <leitao@xxxxxxxxxx>