From: Zheyu Ma zheyuma97@gmail.com
[ Upstream commit 4f01d09b2bbfbcb47b3eb305560a7f4857a32260 ]
When the sm712fb driver writes three bytes to the framebuffer, the driver will crash:
BUG: unable to handle page fault for address: ffffc90001ffffff RIP: 0010:smtcfb_write+0x454/0x5b0 Call Trace: vfs_write+0x291/0xd60 ? do_sys_openat2+0x27d/0x350 ? __fget_light+0x54/0x340 ksys_write+0xce/0x190 do_syscall_64+0x43/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae
Fix it by removing the open-coded endianness fixup-code.
Signed-off-by: Zheyu Ma zheyuma97@gmail.com Signed-off-by: Helge Deller deller@gmx.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/video/fbdev/sm712fb.c | 21 ++++----------------- 1 file changed, 4 insertions(+), 17 deletions(-)
diff --git a/drivers/video/fbdev/sm712fb.c b/drivers/video/fbdev/sm712fb.c index 246681414577..86ce99de5f27 100644 --- a/drivers/video/fbdev/sm712fb.c +++ b/drivers/video/fbdev/sm712fb.c @@ -1130,7 +1130,7 @@ static ssize_t smtcfb_write(struct fb_info *info, const char __user *buf, count = total_size - p; }
- buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count, GFP_KERNEL); + buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!buffer) return -ENOMEM;
@@ -1148,24 +1148,11 @@ static ssize_t smtcfb_write(struct fb_info *info, const char __user *buf, break; }
- for (i = c >> 2; i--;) { - fb_writel(big_swap(*src), dst++); + for (i = (c + 3) >> 2; i--;) { + fb_writel(big_swap(*src), dst); + dst++; src++; } - if (c & 3) { - u8 *src8 = (u8 *)src; - u8 __iomem *dst8 = (u8 __iomem *)dst; - - for (i = c & 3; i--;) { - if (i & 1) { - fb_writeb(*src8++, ++dst8); - } else { - fb_writeb(*src8++, --dst8); - dst8 += 2; - } - } - dst = (u32 __iomem *)dst8; - }
*ppos += c; buf += c;