[Cbe-oss-dev] [PATCH 1/1] Fix another user-visible SPU coredump bug

[Arnd Bergmann]

On Monday 13 August 2007, Michael Ellerman wrote:
> The SPU coredump code has an array of "spufs_coredump_reader"s, each of
> which has either a read or a get callback, as well as the size of the
> data it will generate. Those with read callbacks can generate an arbitrary
> amount of data, however the get callbacks all return a u64, 8 bytes, and
> this is enforced by do_coredump_read().
> 
> There seems to be a bit of confusion however, and some of the get
> callbacks supposedly return quantities other than 8 bytes. It looks as
> though there might have been some ascii vs binary mixup,
> eg. "0x11112222\n" == 11, and "0x1111222233334444\n" == 19.
> 
> Although this bug doesn't lead to unloadable coredumps, it does make the
> contents of the SPU notes incomprehensible to user space (without hacks)
> - so I think we should fix it asap.

Uli just stumbled over this patch and noted that it's the wrong solution.
gdb expects the notes to be in exactly the same format as the file
contents.

This means that the notes sizes were correct, but the content
was incorrectly written in binary form instead of using the
correct format string.

> Paulus, please apply for 23, Jeremy has already acked this. Apologies this
> is late in the cycle, I've only just had time to look into it.
> 
> ---
>  arch/powerpc/platforms/cell/spufs/file.c |   12 ++++++------
>  1 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
> index 4100ddc..240a382 100644
> --- a/arch/powerpc/platforms/cell/spufs/file.c
> +++ b/arch/powerpc/platforms/cell/spufs/file.c
> @@ -2233,14 +2233,14 @@ struct tree_descr spufs_dir_nosched_contents[] = {
>  struct spufs_coredump_reader spufs_coredump_read[] = {
>  	{ "regs", __spufs_regs_read, NULL, 128 * 16 },
>  	{ "fpcr", __spufs_fpcr_read, NULL, 16 },
> -	{ "lslr", NULL, __spufs_lslr_get, 11 },
> -	{ "decr", NULL, __spufs_decr_get, 11 },
> -	{ "decr_status", NULL, __spufs_decr_status_get, 11 },
> +	{ "lslr", NULL, __spufs_lslr_get, 8 },
> +	{ "decr", NULL, __spufs_decr_get, 8 },
> +	{ "decr_status", NULL, __spufs_decr_status_get, 8 },
>  	{ "mem", __spufs_mem_read, NULL, 256 * 1024, },
>  	{ "signal1", __spufs_signal1_read, NULL, 4 },
> -	{ "signal1_type", NULL, __spufs_signal1_type_get, 2 },
> +	{ "signal1_type", NULL, __spufs_signal1_type_get, 8 },
>  	{ "signal2", __spufs_signal2_read, NULL, 4 },
> -	{ "signal2_type", NULL, __spufs_signal2_type_get, 2 },
> +	{ "signal2_type", NULL, __spufs_signal2_type_get, 8 },
>  	{ "event_mask", NULL, __spufs_event_mask_get, 8 },
>  	{ "event_status", NULL, __spufs_event_status_get, 8 },
>  	{ "mbox_info", __spufs_mbox_info_read, NULL, 4 },
> @@ -2248,7 +2248,7 @@ struct spufs_coredump_reader spufs_coredump_read[] = {
>  	{ "wbox_info", __spufs_wbox_info_read, NULL, 16 },
>  	{ "dma_info", __spufs_dma_info_read, NULL, 69 * 8 },
>  	{ "proxydma_info", __spufs_proxydma_info_read, NULL, 35 * 8 },
> -	{ "object-id", NULL, __spufs_object_id_get, 19 },
> +	{ "object-id", NULL, __spufs_object_id_get, 8 },
>  	{ },
>  };
>  int spufs_coredump_num_notes = ARRAY_SIZE(spufs_coredump_read) - 1;