Re: [PATCH 2/2] powerpc/xive: Add a check for memory allocation failure
From: Greg Kurz <hidden>
Date: 2019-08-01 10:57:23
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kernel-janitors, lkml
On Thu, 1 Aug 2019 10:32:42 +0200 Christophe JAILLET [off-list ref] wrote:
The result of this kzalloc is not checked. Add a check and corresponding error handling code. Signed-off-by: Christophe JAILLET <redacted> ---
Reviewed-by: Greg Kurz <redacted>
Note that 'xive_irq_bitmap_add()' failures are not handled in 'xive_spapr_init()' I guess that it is not really an issue. This function is _init, so if a memory allocation occures here, it is likely that the system will already be in bad shape.
Hmm not sure... The allocation could also fail if the "ibm,xive-lisn-ranges" property contains an insanely big range, eg. count == 1 << 31. The system isn't necessarily in bad shape in this case, but XIVE is definitely unusable and we should let a chance to the kernel to switch to XICS in this case. I guess it is worth adding proper error handling in xive_spapr_init() as well.
quoted hunk ↗ jump to hunk
Anyway, the check added here would at least keep the data linked in 'xive_irq_bitmaps' usable. --- arch/powerpc/sysdev/xive/spapr.c | 4 ++++ 1 file changed, 4 insertions(+)diff --git a/arch/powerpc/sysdev/xive/spapr.c b/arch/powerpc/sysdev/xive/spapr.c index b4f5eb9e0f82..52198131c75e 100644 --- a/arch/powerpc/sysdev/xive/spapr.c +++ b/arch/powerpc/sysdev/xive/spapr.c@@ -53,6 +53,10 @@ static int xive_irq_bitmap_add(int base, int count) xibm->base = base; xibm->count = count; xibm->bitmap = kzalloc(xibm->count, GFP_KERNEL); + if (!xibm->bitmap) { + kfree(xibm); + return -ENOMEM; + } list_add(&xibm->list, &xive_irq_bitmaps); pr_info("Using IRQ range [%x-%x]", xibm->base,