[PATCH 5.10 311/545] intel_th: msu: Fix vmalloced buffers

Greg Kroah-Hartman
2022-08-19T16:24:43Z

From: Alexander Shishkin <alexander.shishkin@linux.intel.com>

[ Upstream commit ac12ad3ccf6d386e64a9d6a890595a2509d24edd ]

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.

Fixes: ba39bd830605 ("intel_th: msu: Switch over to scatterlist")
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Link: https://lore.kernel.org/r/20220705082637.59979-4-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 3a77551fb4fc..24f56a7c0fcf 100644
--- a/drivers/hwtracing/intel_th/msu.c
+++ b/drivers/hwtracing/intel_th/msu.c
@@ -1053,6 +1053,16 @@ msc_buffer_set_uc(struct msc_window *win, unsigned int nr_segs) {}
static inline void msc_buffer_set_wb(struct msc_window *win) {}
#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
@@ -1125,7 +1135,7 @@ 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,
@@ -1387,7 +1397,7 @@ 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