From: Borislav Petkov <bp@alien8.de>
Date: Sun, 21 Oct 2012 16:57:56 +0000 (+0200)
Subject: libata debugging: Warn when unable to find timing descriptor based on xfer_mode
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=cd705d5ad49bb8894dda2726dcaef8f63ddeba43;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git

libata debugging: Warn when unable to find timing descriptor based on xfer_mode

ata_timing_find_mode could return NULL which is not checked by all
low-level ATA drivers using it and cause a NULL ptr deref. Warn at least
so that possible issues can get fixed easily.

Signed-off-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
---

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 3cc7096cfda7..f46fbd3bd3fb 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2942,6 +2942,10 @@ const struct ata_timing *ata_timing_find_mode(u8 xfer_mode)
 
 	if (xfer_mode == t->mode)
 		return t;
+
+	WARN_ONCE(true, "%s: unable to find timing for xfer_mode 0x%x\n",
+			__func__, xfer_mode);
+
 	return NULL;
 }