[PATCH 1/6] powerpc/spufs: fix spu_context leak in coredump

[Junrui Luo via B4 Relay <devnull+moonafterrain.outlook.com@kernel.org>]

From: Junrui Luo <moonafterrain@outlook.com>

coredump_next_context() returns a spu_context with a reference taken by
get_spu_context(), which the caller must drop.
spufs_coredump_extra_notes_size() does so on all of its exits, but
spufs_coredump_extra_notes_write() never calls put_spu_context(), so
every context dumped through elf_coredump_extra_notes_write() leaks a
reference, including on the success path.

Fix by dropping the reference on each of the three exits of the loop,
mirroring ..._size().

Fixes: 38b407be172d ("powerpc/spufs: Rework fcheck() usage")
Reported-by: Yuhao Jiang <danisjiang@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Junrui Luo <moonafterrain@outlook.com>
---
 arch/powerpc/platforms/cell/spufs/coredump.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/cell/spufs/coredump.c b/arch/powerpc/platforms/cell/spufs/coredump.c
index 301ee7d8b7df..f5964c9ebb3e 100644
--- a/arch/powerpc/platforms/cell/spufs/coredump.c
+++ b/arch/powerpc/platforms/cell/spufs/coredump.c
@@ -162,13 +162,16 @@ int spufs_coredump_extra_notes_write(struct coredump_params *cprm)
 	fd = 0;
 	while ((ctx = coredump_next_context(&fd)) != NULL) {
 		rc = spu_acquire_saved(ctx);
-		if (rc)
+		if (rc) {
+			put_spu_context(ctx);
 			return rc;
+		}
 
 		for (j = 0; spufs_coredump_read[j].name != NULL; j++) {
 			rc = spufs_arch_write_note(ctx, j, cprm, fd);
 			if (rc) {
 				spu_release_saved(ctx);
+				put_spu_context(ctx);
 				return rc;
 			}
 		}
@@ -177,6 +180,7 @@ int spufs_coredump_extra_notes_write(struct coredump_params *cprm)
 
 		/* start searching the next fd next time */
 		fd++;
+		put_spu_context(ctx);
 	}
 
 	return 0;

-- 
2.51.2