| Message ID | 98b79fbdde69a4a203096eb9c8801045c5a055fb.1690218016.git.geert+renesas@glider.be (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Revert "fbcon: Use kzalloc() in fbcon_prepare_logo()" | expand |
On 2023/07/25 2:03, Geert Uytterhoeven wrote: > The syzbot report turned out to be a false possitive, caused by a KMSAN > problem. Indeed, after allocating the buffer, it is fully initialized > using scr_memsetw(). Hence there is no point in allocating zeroed > memory, while this does incur some overhead. I suggest using below description, for this problem was reported by me using a kernel built with syzbot's config file (i.e. syzbot is irrelevant). Commit a6a00d7e8ffd ("fbcon: Use kzalloc() in fbcon_prepare_logo()") is redundant, for the root cause that resulted in a false positive was fixed by commit 27f644dc5a77 ("x86: kmsan: use C versions of memset16/memset32/ memset64").
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c index 8e76bc246b3871b0..0246948f3c81a7a6 100644 --- a/drivers/video/fbdev/core/fbcon.c +++ b/drivers/video/fbdev/core/fbcon.c @@ -577,7 +577,7 @@ static void fbcon_prepare_logo(struct vc_data *vc, struct fb_info *info, if (scr_readw(r) != vc->vc_video_erase_char) break; if (r != q && new_rows >= rows + logo_lines) { - save = kzalloc(array3_size(logo_lines, new_cols, 2), + save = kmalloc(array3_size(logo_lines, new_cols, 2), GFP_KERNEL); if (save) { int i = min(cols, new_cols);
This reverts commit a6a00d7e8ffd78d1cdb7a43f1278f081038c638f. The syzbot report turned out to be a false possitive, caused by a KMSAN problem. Indeed, after allocating the buffer, it is fully initialized using scr_memsetw(). Hence there is no point in allocating zeroed memory, while this does incur some overhead. Closes: https://lore.kernel.org/r/CAMuHMdUH4CU9EfoirSxjivg08FDimtstn7hizemzyQzYeq6b6g@mail.gmail.com/ Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> --- drivers/video/fbdev/core/fbcon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)