| Message ID | 20230120100623.3530634-1-shravan.chippa@microchip.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 57074e6822142beb47d365c3b1286c218ba68ec7 |
| Headers | show |
| Series | [v1] dmaengine: sf-pdma: pdma_desc memory leak fix | expand |
Hey Shravan, On Fri, Jan 20, 2023 at 03:36:23PM +0530, shravan kumar wrote: > From: Shravan Chippa <shravan.chippa@microchip.com> > > Commit b2cc5c465c2c ("dmaengine: sf-pdma: Add multithread support for a > DMA channel") changed sf_pdma_prep_dma_memcpy() to unconditionally > allocate a new sf_pdma_desc each time it is called. > > The driver previously recycled descs, by checking the in_use flag, only > allocating additional descs if the existing one was in use. This logic > was removed in commit b2cc5c465c2c ("dmaengine: sf-pdma: Add multithread > support for a DMA channel"), but sf_pdma_free_desc() was not changed to > handle the new behaviour. > > As a result, each time sf_pdma_prep_dma_memcpy() is called, the previous > descriptor is leaked, over time leading to memory starvation: > > unreferenced object 0xffffffe008447300 (size 192): > comm "irq/39-mchp_dsc", pid 343, jiffies 4294906910 (age 981.200s) > hex dump (first 32 bytes): > 00 00 00 ff 00 00 00 00 b8 c1 00 00 00 00 00 00 ................ > 00 00 70 08 10 00 00 00 00 00 00 c0 00 00 00 00 ..p............. > backtrace: > [<00000000064a04f4>] kmemleak_alloc+0x1e/0x28 > [<00000000018927a7>] kmem_cache_alloc+0x11e/0x178 > [<000000002aea8d16>] sf_pdma_prep_dma_memcpy+0x40/0x112 > > Add the missing kfree() to sf_pdma_free_desc(), and remove the redundant > in_use flag. > > Fixes: b2cc5c465c2c ("dmaengine: sf-pdma: Add multithread support for a DMA channel") > Signed-off-by: Shravan Chippa <shravan.chippa@microchip.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Thanks, Conor.
Hey Vinod, On Fri, Jan 20, 2023 at 03:36:23PM +0530, shravan kumar wrote: > From: Shravan Chippa <shravan.chippa@microchip.com> > > Commit b2cc5c465c2c ("dmaengine: sf-pdma: Add multithread support for a > DMA channel") changed sf_pdma_prep_dma_memcpy() to unconditionally > allocate a new sf_pdma_desc each time it is called. > > The driver previously recycled descs, by checking the in_use flag, only > allocating additional descs if the existing one was in use. This logic > was removed in commit b2cc5c465c2c ("dmaengine: sf-pdma: Add multithread > support for a DMA channel"), but sf_pdma_free_desc() was not changed to > handle the new behaviour. > > As a result, each time sf_pdma_prep_dma_memcpy() is called, the previous > descriptor is leaked, over time leading to memory starvation: > > unreferenced object 0xffffffe008447300 (size 192): > comm "irq/39-mchp_dsc", pid 343, jiffies 4294906910 (age 981.200s) > hex dump (first 32 bytes): > 00 00 00 ff 00 00 00 00 b8 c1 00 00 00 00 00 00 ................ > 00 00 70 08 10 00 00 00 00 00 00 c0 00 00 00 00 ..p............. > backtrace: > [<00000000064a04f4>] kmemleak_alloc+0x1e/0x28 > [<00000000018927a7>] kmem_cache_alloc+0x11e/0x178 > [<000000002aea8d16>] sf_pdma_prep_dma_memcpy+0x40/0x112 > > Add the missing kfree() to sf_pdma_free_desc(), and remove the redundant > in_use flag. > > Fixes: b2cc5c465c2c ("dmaengine: sf-pdma: Add multithread support for a DMA channel") > Signed-off-by: Shravan Chippa <shravan.chippa@microchip.com> Just checking in to make sure that this patch is on your radar. Is there something you're waiting for on it? Cheers, Conor. > --- > drivers/dma/sf-pdma/sf-pdma.c | 3 +-- > drivers/dma/sf-pdma/sf-pdma.h | 1 - > 2 files changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/dma/sf-pdma/sf-pdma.c b/drivers/dma/sf-pdma/sf-pdma.c > index 6b524eb6bcf3..e578ad556949 100644 > --- a/drivers/dma/sf-pdma/sf-pdma.c > +++ b/drivers/dma/sf-pdma/sf-pdma.c > @@ -96,7 +96,6 @@ sf_pdma_prep_dma_memcpy(struct dma_chan *dchan, dma_addr_t dest, dma_addr_t src, > if (!desc) > return NULL; > > - desc->in_use = true; > desc->dirn = DMA_MEM_TO_MEM; > desc->async_tx = vchan_tx_prep(&chan->vchan, &desc->vdesc, flags); > > @@ -290,7 +289,7 @@ static void sf_pdma_free_desc(struct virt_dma_desc *vdesc) > struct sf_pdma_desc *desc; > > desc = to_sf_pdma_desc(vdesc); > - desc->in_use = false; > + kfree(desc); > } > > static void sf_pdma_donebh_tasklet(struct tasklet_struct *t) > diff --git a/drivers/dma/sf-pdma/sf-pdma.h b/drivers/dma/sf-pdma/sf-pdma.h > index dcb3687bd5da..5c398a83b491 100644 > --- a/drivers/dma/sf-pdma/sf-pdma.h > +++ b/drivers/dma/sf-pdma/sf-pdma.h > @@ -78,7 +78,6 @@ struct sf_pdma_desc { > u64 src_addr; > struct virt_dma_desc vdesc; > struct sf_pdma_chan *chan; > - bool in_use; > enum dma_transfer_direction dirn; > struct dma_async_tx_descriptor *async_tx; > }; > -- > 2.34.1 >
On 20-01-23, 15:36, shravan kumar wrote: > From: Shravan Chippa <shravan.chippa@microchip.com> > > Commit b2cc5c465c2c ("dmaengine: sf-pdma: Add multithread support for a > DMA channel") changed sf_pdma_prep_dma_memcpy() to unconditionally > allocate a new sf_pdma_desc each time it is called. > > The driver previously recycled descs, by checking the in_use flag, only > allocating additional descs if the existing one was in use. This logic > was removed in commit b2cc5c465c2c ("dmaengine: sf-pdma: Add multithread > support for a DMA channel"), but sf_pdma_free_desc() was not changed to > handle the new behaviour. > > As a result, each time sf_pdma_prep_dma_memcpy() is called, the previous > descriptor is leaked, over time leading to memory starvation: > > unreferenced object 0xffffffe008447300 (size 192): > comm "irq/39-mchp_dsc", pid 343, jiffies 4294906910 (age 981.200s) > hex dump (first 32 bytes): > 00 00 00 ff 00 00 00 00 b8 c1 00 00 00 00 00 00 ................ > 00 00 70 08 10 00 00 00 00 00 00 c0 00 00 00 00 ..p............. > backtrace: > [<00000000064a04f4>] kmemleak_alloc+0x1e/0x28 > [<00000000018927a7>] kmem_cache_alloc+0x11e/0x178 > [<000000002aea8d16>] sf_pdma_prep_dma_memcpy+0x40/0x112 > > Add the missing kfree() to sf_pdma_free_desc(), and remove the redundant > in_use flag. Applied, thanks
diff --git a/drivers/dma/sf-pdma/sf-pdma.c b/drivers/dma/sf-pdma/sf-pdma.c index 6b524eb6bcf3..e578ad556949 100644 --- a/drivers/dma/sf-pdma/sf-pdma.c +++ b/drivers/dma/sf-pdma/sf-pdma.c @@ -96,7 +96,6 @@ sf_pdma_prep_dma_memcpy(struct dma_chan *dchan, dma_addr_t dest, dma_addr_t src, if (!desc) return NULL; - desc->in_use = true; desc->dirn = DMA_MEM_TO_MEM; desc->async_tx = vchan_tx_prep(&chan->vchan, &desc->vdesc, flags); @@ -290,7 +289,7 @@ static void sf_pdma_free_desc(struct virt_dma_desc *vdesc) struct sf_pdma_desc *desc; desc = to_sf_pdma_desc(vdesc); - desc->in_use = false; + kfree(desc); } static void sf_pdma_donebh_tasklet(struct tasklet_struct *t) diff --git a/drivers/dma/sf-pdma/sf-pdma.h b/drivers/dma/sf-pdma/sf-pdma.h index dcb3687bd5da..5c398a83b491 100644 --- a/drivers/dma/sf-pdma/sf-pdma.h +++ b/drivers/dma/sf-pdma/sf-pdma.h @@ -78,7 +78,6 @@ struct sf_pdma_desc { u64 src_addr; struct virt_dma_desc vdesc; struct sf_pdma_chan *chan; - bool in_use; enum dma_transfer_direction dirn; struct dma_async_tx_descriptor *async_tx; };