From: Borislav Petkov Date: Thu, 16 Jun 2016 17:13:49 +0000 (+0200) Subject: x86/amd_nb: Fix boot crash on non-AMD systems X-Git-Tag: firefly_0821_release~176^2~4^2~37^2~122 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=d9c5952f0aa481d0b703e05dd1ba6eca374d2dbc;p=firefly-linux-kernel-4.4.55.git x86/amd_nb: Fix boot crash on non-AMD systems commit 1ead852dd88779eda12cb09cc894a03d9abfe1ec upstream. Fix boot crash that triggers if this driver is built into a kernel and run on non-AMD systems. AMD northbridges users call amd_cache_northbridges() and it returns a negative value to signal that we weren't able to cache/detect any northbridges on the system. At least, it should do so as all its callers expect it to do so. But it does return a negative value only when kmalloc() fails. Fix it to return -ENODEV if there are no NBs cached as otherwise, amd_nb users like amd64_edac, for example, which relies on it to know whether it should load or not, gets loaded on systems like Intel Xeons where it shouldn't. Reported-and-tested-by: Tony Battersby Signed-off-by: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1466097230-5333-2-git-send-email-bp@alien8.de Link: https://lkml.kernel.org/r/5761BEB0.9000807@cybernetics.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c index 29fa475ec518..c986d0b3bc35 100644 --- a/arch/x86/kernel/amd_nb.c +++ b/arch/x86/kernel/amd_nb.c @@ -71,8 +71,8 @@ int amd_cache_northbridges(void) while ((misc = next_northbridge(misc, amd_nb_misc_ids)) != NULL) i++; - if (i == 0) - return 0; + if (!i) + return -ENODEV; nb = kzalloc(i * sizeof(struct amd_northbridge), GFP_KERNEL); if (!nb)