From: Gustav Wiklander gustavwi@axis.com
[ Upstream commit b59a7ca15464c78ea1ba3b280cfc5ac5ece11ade ]
In the prepare_message callback the bus driver has the opportunity to split a transfer into smaller chunks. spi_map_msg is done after prepare_message.
Function spi_res_release releases the splited transfers in the message. Therefore spi_res_release should be called after spi_map_msg.
The previous try at this was commit c9ba7a16d0f1 which released the splited transfers after spi_finalize_current_message had been called. This introduced a race since the message struct could be out of scope because the spi_sync call got completed.
Fixes this leak on spi bus driver spi-bcm2835.c when transfer size is greater than 65532:
Kmemleak: sg_alloc_table+0x28/0xc8 spi_map_buf+0xa4/0x300 __spi_pump_messages+0x370/0x748 __spi_sync+0x1d4/0x270 spi_sync+0x34/0x58 spi_test_execute_msg+0x60/0x340 [spi_loopback_test] spi_test_run_iter+0x548/0x578 [spi_loopback_test] spi_test_run_test+0x94/0x140 [spi_loopback_test] spi_test_run_tests+0x150/0x180 [spi_loopback_test] spi_loopback_test_probe+0x50/0xd0 [spi_loopback_test] spi_drv_probe+0x84/0xe0
Signed-off-by: Gustav Wiklander gustavwi@axis.com Link: https://lore.kernel.org/r/20200908151129.15915-1-gustav.wiklander@axis.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/spi/spi.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 5c5a95792c0d3..65ca552654794 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1305,8 +1305,6 @@ out: if (msg->status && ctlr->handle_err) ctlr->handle_err(ctlr, msg);
- spi_res_release(ctlr, msg); - spi_finalize_current_message(ctlr);
return ret; @@ -1694,6 +1692,13 @@ void spi_finalize_current_message(struct spi_controller *ctlr)
spi_unmap_msg(ctlr, mesg);
+ /* In the prepare_messages callback the spi bus has the opportunity to + * split a transfer to smaller chunks. + * Release splited transfers here since spi_map_msg is done on the + * splited transfers. + */ + spi_res_release(ctlr, mesg); + if (ctlr->cur_msg_prepared && ctlr->unprepare_message) { ret = ctlr->unprepare_message(ctlr, mesg); if (ret) {