fbdev: fix WARNING in __alloc_pages_nodemask bug

commit 8c40292be9169a9cbe19aadd1a6fc60cbd1af82f upstream.

Syzkaller hit 'WARNING in __alloc_pages_nodemask' bug.

WARNING: CPU: 1 PID: 1473 at mm/page_alloc.c:4377
__alloc_pages_nodemask+0x4da/0x2130
Kernel panic - not syncing: panic_on_warn set ...

Call Trace:
 alloc_pages_current+0xb1/0x1e0
 kmalloc_order+0x1f/0x60
 kmalloc_order_trace+0x1d/0x120
 fb_alloc_cmap_gfp+0x85/0x2b0
 fb_set_user_cmap+0xff/0x370
 do_fb_ioctl+0x949/0xa20
 fb_ioctl+0xdd/0x120
 do_vfs_ioctl+0x186/0x1070
 ksys_ioctl+0x89/0xa0
 __x64_sys_ioctl+0x74/0xb0
 do_syscall_64+0xc8/0x550
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

This is a warning about order >= MAX_ORDER and the order is from
userspace ioctl. Add flag __NOWARN to silence this warning.

Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/video/fbdev/core/fbcmap.c b/drivers/video/fbdev/core/fbcmap.c
index 68a113594808f220aa818424cd6e342897806a74..2811c4afde01c0e507c6d163410f8084b67bfa7f 100644 (file)
--- a/drivers/video/fbdev/core/fbcmap.c
+++ b/drivers/video/fbdev/core/fbcmap.c
@@ -94,6 +94,8 @@ int fb_alloc_cmap_gfp(struct fb_cmap *cmap, int len, int transp, gfp_t flags)
        int size = len * sizeof(u16);
        int ret = -ENOMEM;
 
+       flags |= __GFP_NOWARN;
+
        if (cmap->len != len) {
                fb_dealloc_cmap(cmap);
                if (!len)