| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <5e01b376-b905-4775-badf-41d31d2a821c@arm.com>
Date: Mon, 21 Oct 2024 11:38:44 +0100
From: Robin Murphy <robin.murphy@....com>
To: Sean Anderson <sean.anderson@...ux.dev>, Christoph Hellwig <hch@....de>,
iommu@...ts.linux.dev
Cc: linux-trace-kernel@...r.kernel.org, Masami Hiramatsu
<mhiramat@...nel.org>, linux-kernel@...r.kernel.org,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Steven Rostedt <rostedt@...dmis.org>,
Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH 3/3] dma-mapping: Trace more error paths
On 2024-10-17 7:13 pm, Sean Anderson wrote:
> It can be surprising to the user if DMA functions are only traced on
> success. On failure, it can be unclear what the source of the problem
> is. Fix this by tracing all functions even when they fail. Cases where
> we BUG/WARN are skipped, since those should be sufficiently noisy
> already.
>
> Signed-off-by: Sean Anderson <sean.anderson@...ux.dev>
> ---
>
> include/trace/events/dma.h | 41 ++++++++++++++++++++++++++++++++++++++
> kernel/dma/mapping.c | 27 +++++++++++++++++--------
> 2 files changed, 60 insertions(+), 8 deletions(-)
>
> diff --git a/include/trace/events/dma.h b/include/trace/events/dma.h
> index 9bc647f9ad4d..321cce327404 100644
> --- a/include/trace/events/dma.h
> +++ b/include/trace/events/dma.h
> @@ -161,6 +161,12 @@ DEFINE_EVENT(_dma_alloc, dma_alloc_pages,
> unsigned long attrs),
> TP_ARGS(dev, virt_addr, dma_addr, size, dir, flags, attrs));
>
> +DEFINE_EVENT(_dma_alloc, dma_alloc_sgt_err,
> + TP_PROTO(struct device *dev, void *virt_addr, dma_addr_t dma_addr,
> + size_t size, enum dma_data_direction dir, gfp_t flags,
> + unsigned long attrs),
> + TP_ARGS(dev, virt_addr, dma_addr, size, dir, flags, attrs));
> +
> TRACE_EVENT(dma_alloc_sgt,
> TP_PROTO(struct device *dev, struct sg_table *sgt, size_t size,
> enum dma_data_direction dir, gfp_t flags, unsigned long attrs),
> @@ -325,6 +331,41 @@ TRACE_EVENT(dma_map_sg,
> decode_dma_attrs(__entry->attrs))
> );
>
> +TRACE_EVENT(dma_map_sg_err,
> + TP_PROTO(struct device *dev, struct scatterlist *sgl, int nents,
> + int err, enum dma_data_direction dir, unsigned long attrs),
> + TP_ARGS(dev, sgl, nents, err, dir, attrs),
> +
> + TP_STRUCT__entry(
> + __string(device, dev_name(dev))
> + __dynamic_array(u64, phys_addrs, nents)
> + __field(int, err)
> + __field(enum dma_data_direction, dir)
> + __field(unsigned long, attrs)
> + ),
> +
> + TP_fast_assign(
> + struct scatterlist *sg;
> + int i;
> +
> + __assign_str(device);
> + for_each_sg(sgl, sg, nents, i)
> + ((u64 *)__get_dynamic_array(phys_addrs))[i] = sg_phys(sg);
> + __entry->err = err;
> + __entry->dir = dir;
> + __entry->attrs = attrs;
> + ),
> +
> + TP_printk("%s dir=%s dma_addrs=%s err=%d attrs=%s",
> + __get_str(device),
> + decode_dma_data_direction(__entry->dir),
> + __print_array(__get_dynamic_array(phys_addrs),
> + __get_dynamic_array_len(phys_addrs) /
> + sizeof(u64), sizeof(u64)),
> + __entry->err,
> + decode_dma_attrs(__entry->attrs))
> +);
> +
> TRACE_EVENT(dma_unmap_sg,
> TP_PROTO(struct device *dev, struct scatterlist *sgl, int nents,
> enum dma_data_direction dir, unsigned long attrs),
> diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
> index b8a6bc492fae..636dbb0629a4 100644
> --- a/kernel/dma/mapping.c
> +++ b/kernel/dma/mapping.c
> @@ -223,6 +223,7 @@ static int __dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
> debug_dma_map_sg(dev, sg, nents, ents, dir, attrs);
> } else if (WARN_ON_ONCE(ents != -EINVAL && ents != -ENOMEM &&
> ents != -EIO && ents != -EREMOTEIO)) {
> + trace_dma_map_sg_err(dev, sg, nents, ents, dir, attrs);
Isn't this just a case of moving the existing tracepoint up outside the
"if (ents > 0)" condition?
> return -EIO;
> }
>
> @@ -604,20 +605,26 @@ void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
> if (WARN_ON_ONCE(flag & __GFP_COMP))
> return NULL;
>
> - if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr))
> + if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr)) {
> + trace_dma_alloc(dev, cpu_addr, *dma_handle, size,
> + DMA_BIDIRECTIONAL, flag, attrs);
> return cpu_addr;
> + }
>
> /* let the implementation decide on the zone to allocate from: */
> flag &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM);
>
> - if (dma_alloc_direct(dev, ops))
> + if (dma_alloc_direct(dev, ops)) {
> cpu_addr = dma_direct_alloc(dev, size, dma_handle, flag, attrs);
> - else if (use_dma_iommu(dev))
> + } else if (use_dma_iommu(dev)) {
> cpu_addr = iommu_dma_alloc(dev, size, dma_handle, flag, attrs);
> - else if (ops->alloc)
> + } else if (ops->alloc) {
> cpu_addr = ops->alloc(dev, size, dma_handle, flag, attrs);
> - else
> + } else {
> + trace_dma_alloc(dev, NULL, 0, size, DMA_BIDIRECTIONAL, flag,
> + attrs);
> return NULL;
Similarly just move this return down past the tracepoint, same as the
hunk below?
> + }
>
> trace_dma_alloc(dev, cpu_addr, *dma_handle, size, DMA_BIDIRECTIONAL,
> flag, attrs);
> @@ -642,11 +649,11 @@ void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
> */
> WARN_ON(irqs_disabled());
>
> - if (!cpu_addr)
> - return;
> -
> trace_dma_free(dev, cpu_addr, dma_handle, size, DMA_BIDIRECTIONAL,
> attrs);
> + if (!cpu_addr)
> + return;
> +
> debug_dma_free_coherent(dev, size, cpu_addr, dma_handle);
> if (dma_alloc_direct(dev, ops))
> dma_direct_free(dev, size, cpu_addr, dma_handle, attrs);
> @@ -688,6 +695,8 @@ struct page *dma_alloc_pages(struct device *dev, size_t size,
> trace_dma_alloc_pages(dev, page_to_virt(page), *dma_handle,
> size, dir, gfp, 0);
> debug_dma_map_page(dev, page, 0, size, dir, *dma_handle, 0);
> + } else {
> + trace_dma_alloc_pages(dev, NULL, 0, size, dir, gfp, 0);
Could we move the page_to_virt() into the event definiton and let that
handle NULL, then similarly hoist the tracepoint out of the condition?
> }
> return page;
> }
> @@ -772,6 +781,8 @@ struct sg_table *dma_alloc_noncontiguous(struct device *dev, size_t size,
> sgt->nents = 1;
> trace_dma_alloc_sgt(dev, sgt, size, dir, gfp, attrs);
> debug_dma_map_sg(dev, sgt->sgl, sgt->orig_nents, 1, dir, attrs);
> + } else {
> + trace_dma_alloc_sgt_err(dev, NULL, 0, size, gfp, dir, attrs);
And again similarly here - if I'm interested in calls to
dma_alloc_contiguous(), I'd rather have a "dma_alloc_contiguous"
tracepoint which can tell me both the arguments and the result at a
glance, than have to remember to trace two distinct other things based
on internal details.
Thanks,
Robin.
> }
> return sgt;
> }
Powered by blists - more mailing lists