[PATCH v3 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.nih...@gmail.com>
---
v2->v3: No change
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