[PATCH v2 1/2] staging: fbtft: fix potential memory leak in fbtft_framebuffer_alloc()

[Abdun Nihaal]

After commit 56c134f7f1b5 ("fbdev: Track deferred-I/O pages in pageref
struct"), fb_deferred_io_init() allocates memory for info->pagerefs as
well as return an error code on failure. However the error code is
ignored here and the memory allocated could leak because of not calling
fb_deferred_io_cleanup() on the error path.

Fix them by adding the cleanup function on the error path, and handling
the error code returned by fb_deferred_io_init().

Fixes: 56c134f7f1b5 ("fbdev: Track deferred-I/O pages in pageref struct")
Signed-off-by: Abdun Nihaal <abdun.nihaal at gmail.com>
---
v1->v2:
- Handle the error code returned by fb_deferred_io_init correctly
- Update Fixes tag to point to the commit that introduced the memory
  allocation which leads to the leak.

 drivers/staging/fbtft/fbtft-core.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/fbtft/fbtft-core.c
index da9c64152a60..8538b6bab6a5 100644
--- a/drivers/staging/fbtft/fbtft-core.c
+++ b/drivers/staging/fbtft/fbtft-core.c
@@ -612,7 +612,8 @@ struct fb_info *fbtft_framebuffer_alloc(struct fbtft_display *display,
 	info->fix.line_length =    width * bpp / 8;
 	info->fix.accel =          FB_ACCEL_NONE;
 	info->fix.smem_len =       vmem_size;
-	fb_deferred_io_init(info);
+	if (fb_deferred_io_init(info))
+		goto release_framebuf;
 
 	info->var.rotate =         pdata->rotate;
 	info->var.xres =           width;
@@ -652,7 +653,7 @@ struct fb_info *fbtft_framebuffer_alloc(struct fbtft_display *display,
 	if (par->gamma.curves && gamma) {
 		if (fbtft_gamma_parse_str(par, par->gamma.curves, gamma,
 					  strlen(gamma)))
-			goto release_framebuf;
+			goto cleanup_deferred;
 	}
 
 	/* Transmit buffer */
@@ -669,7 +670,7 @@ struct fb_info *fbtft_framebuffer_alloc(struct fbtft_display *display,
 	if (txbuflen > 0) {
 		txbuf = devm_kzalloc(par->info->device, txbuflen, GFP_KERNEL);
 		if (!txbuf)
-			goto release_framebuf;
+			goto cleanup_deferred;
 		par->txbuf.buf = txbuf;
 		par->txbuf.len = txbuflen;
 	}
@@ -691,6 +692,8 @@ struct fb_info *fbtft_framebuffer_alloc(struct fbtft_display *display,
 
 	return info;
 
+cleanup_deferred:
+	fb_deferred_io_cleanup(info);
 release_framebuf:
 	framebuffer_release(info);
 
-- 
2.43.0