linux-kernel - [PATCH 3/6] intel_th: msu: Fix vmalloced buffers

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Date:   Tue,  5 Jul 2022 11:26:34 +0300
From:   Alexander Shishkin <alexander.shishkin@...ux.intel.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH 3/6] intel_th: msu: Fix vmalloced buffers

After commit f5ff79fddf0e ("dma-mapping: remove CONFIG_DMA_REMAP") there's
a chance of DMA buffer getting allocated via vmalloc(), which messes up
the mmapping code:

> RIP: msc_mmap_fault [intel_th_msu]
> Call Trace:
>  <TASK>
>  __do_fault
>  do_fault
...

Fix this by accounting for vmalloc possibility.

Signed-off-by: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Fixes: ba39bd830605 ("intel_th: msu: Switch over to scatterlist")
---
 drivers/hwtracing/intel_th/msu.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c
index 70a07b4e9967..6c8215a47a60 100644
--- a/drivers/hwtracing/intel_th/msu.c
+++ b/drivers/hwtracing/intel_th/msu.c
@@ -1067,6 +1067,16 @@ msc_buffer_set_uc(struct msc *msc) {}
 static inline void msc_buffer_set_wb(struct msc *msc) {}
 #endif /* CONFIG_X86 */
 
+static struct page *msc_sg_page(struct scatterlist *sg)
+{
+	void *addr = sg_virt(sg);
+
+	if (is_vmalloc_addr(addr))
+		return vmalloc_to_page(addr);
+
+	return sg_page(sg);
+}
+
 /**
  * msc_buffer_win_alloc() - alloc a window for a multiblock mode
  * @msc:	MSC device
@@ -1137,7 +1147,7 @@ static void __msc_buffer_win_free(struct msc *msc, struct msc_window *win)
 	int i;
 
 	for_each_sg(win->sgt->sgl, sg, win->nr_segs, i) {
-		struct page *page = sg_page(sg);
+		struct page *page = msc_sg_page(sg);
 
 		page->mapping = NULL;
 		dma_free_coherent(msc_dev(win->msc)->parent->parent, PAGE_SIZE,
@@ -1401,7 +1411,7 @@ static struct page *msc_buffer_get_page(struct msc *msc, unsigned long pgoff)
 	pgoff -= win->pgoff;
 
 	for_each_sg(win->sgt->sgl, sg, win->nr_segs, blk) {
-		struct page *page = sg_page(sg);
+		struct page *page = msc_sg_page(sg);
 		size_t pgsz = PFN_DOWN(sg->length);
 
 		if (pgoff < pgsz)
-- 
2.35.1