| Message ID | 20240822105933.2644945-4-quic_ekangupt@quicinc.com |
|---|---|
| State | New |
| Headers | show |
| Series | Add missing fixes to FastRPC driver | expand |
On Thu, Aug 22, 2024 at 04:29:33PM GMT, Ekansh Gupta wrote: > If multiple dma handles are passed with same fd over a remote call > the kernel driver takes a reference and expects that put for the > map will be called as many times to free the map. > But DSP only > updates the fd one time in the fd list when the DSP refcount > goes to zero I'm sorry, I couldn't understand this phrase. Could you plese clarify what do you mean here? > and hence kernel make put call only once for the > fd. This can cause SMMU fault issue as the same fd can be used > in future for some other call. > > Fixes: 35a82b87135d ("misc: fastrpc: Add dma handle implementation") > Cc: stable <stable@kernel.org> > Signed-off-by: Ekansh Gupta <quic_ekangupt@quicinc.com> > --- > drivers/misc/fastrpc.c | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) > > diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c > index ebe828770a8d..ad56e918e1f8 100644 > --- a/drivers/misc/fastrpc.c > +++ b/drivers/misc/fastrpc.c > @@ -755,7 +755,7 @@ static const struct dma_buf_ops fastrpc_dma_buf_ops = { > > static int fastrpc_map_create(struct fastrpc_user *fl, int fd, > u64 va, u64 len, u32 attr, > - struct fastrpc_map **ppmap) > + struct fastrpc_map **ppmap, bool take_ref) > { > struct fastrpc_session_ctx *sess = fl->sctx; > struct fastrpc_map *map = NULL; > @@ -763,7 +763,7 @@ static int fastrpc_map_create(struct fastrpc_user *fl, int fd, > struct scatterlist *sgl = NULL; > int err = 0, sgl_index = 0; > > - if (!fastrpc_map_lookup(fl, fd, va, len, ppmap, true)) > + if (!fastrpc_map_lookup(fl, fd, va, len, ppmap, take_ref)) > return 0; > > map = kzalloc(sizeof(*map), GFP_KERNEL); > @@ -917,14 +917,17 @@ static int fastrpc_create_maps(struct fastrpc_invoke_ctx *ctx) > int i, err; > > for (i = 0; i < ctx->nscalars; ++i) { > + bool take_ref = true; > > if (ctx->args[i].fd == 0 || ctx->args[i].fd == -1 || > ctx->args[i].length == 0) > continue; > > + if (i >= ctx->nbufs) > + take_ref = false; Please clarify too. > err = fastrpc_map_create(ctx->fl, ctx->args[i].fd, > (u64)ctx->args[i].ptr, ctx->args[i].length, > - ctx->args[i].attr, &ctx->maps[i]); > + ctx->args[i].attr, &ctx->maps[i], take_ref); > if (err) { > dev_err(dev, "Error Creating map %d\n", err); > return -EINVAL; > @@ -1417,7 +1420,7 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl, > > if (init.filelen && init.filefd) { > err = fastrpc_map_create(fl, init.filefd, init.file, > - init.filelen, 0, &map); > + init.filelen, 0, &map, true); > if (err) > goto err; > } > @@ -2040,7 +2043,7 @@ static int fastrpc_req_mem_map(struct fastrpc_user *fl, char __user *argp) > > /* create SMMU mapping */ > err = fastrpc_map_create(fl, req.fd, req.vaddrin, req.length, > - 0, &map); > + 0, &map, true); > if (err) { > dev_err(dev, "failed to map buffer, fd = %d\n", req.fd); > return err; > -- > 2.34.1 >
diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index ebe828770a8d..ad56e918e1f8 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -755,7 +755,7 @@ static const struct dma_buf_ops fastrpc_dma_buf_ops = { static int fastrpc_map_create(struct fastrpc_user *fl, int fd, u64 va, u64 len, u32 attr, - struct fastrpc_map **ppmap) + struct fastrpc_map **ppmap, bool take_ref) { struct fastrpc_session_ctx *sess = fl->sctx; struct fastrpc_map *map = NULL; @@ -763,7 +763,7 @@ static int fastrpc_map_create(struct fastrpc_user *fl, int fd, struct scatterlist *sgl = NULL; int err = 0, sgl_index = 0; - if (!fastrpc_map_lookup(fl, fd, va, len, ppmap, true)) + if (!fastrpc_map_lookup(fl, fd, va, len, ppmap, take_ref)) return 0; map = kzalloc(sizeof(*map), GFP_KERNEL); @@ -917,14 +917,17 @@ static int fastrpc_create_maps(struct fastrpc_invoke_ctx *ctx) int i, err; for (i = 0; i < ctx->nscalars; ++i) { + bool take_ref = true; if (ctx->args[i].fd == 0 || ctx->args[i].fd == -1 || ctx->args[i].length == 0) continue; + if (i >= ctx->nbufs) + take_ref = false; err = fastrpc_map_create(ctx->fl, ctx->args[i].fd, (u64)ctx->args[i].ptr, ctx->args[i].length, - ctx->args[i].attr, &ctx->maps[i]); + ctx->args[i].attr, &ctx->maps[i], take_ref); if (err) { dev_err(dev, "Error Creating map %d\n", err); return -EINVAL; @@ -1417,7 +1420,7 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl, if (init.filelen && init.filefd) { err = fastrpc_map_create(fl, init.filefd, init.file, - init.filelen, 0, &map); + init.filelen, 0, &map, true); if (err) goto err; } @@ -2040,7 +2043,7 @@ static int fastrpc_req_mem_map(struct fastrpc_user *fl, char __user *argp) /* create SMMU mapping */ err = fastrpc_map_create(fl, req.fd, req.vaddrin, req.length, - 0, &map); + 0, &map, true); if (err) { dev_err(dev, "failed to map buffer, fd = %d\n", req.fd); return err;
If multiple dma handles are passed with same fd over a remote call the kernel driver takes a reference and expects that put for the map will be called as many times to free the map. But DSP only updates the fd one time in the fd list when the DSP refcount goes to zero and hence kernel make put call only once for the fd. This can cause SMMU fault issue as the same fd can be used in future for some other call. Fixes: 35a82b87135d ("misc: fastrpc: Add dma handle implementation") Cc: stable <stable@kernel.org> Signed-off-by: Ekansh Gupta <quic_ekangupt@quicinc.com> --- drivers/misc/fastrpc.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)