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authorGustav Wiklander <gustavwi@axis.com>2020-09-08 17:11:29 +0200
committerMark Brown <broonie@kernel.org>2020-09-09 15:11:43 +0100
commitb59a7ca15464c78ea1ba3b280cfc5ac5ece11ade (patch)
tree89bf97bed1b2b9c004656385f622a583f277c02e /drivers
parent83048015ff7710b46e7c489458a93c6fe348229d (diff)
spi: Fix memory leak on splited transfers
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/spi/spi.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 92b8fb416dca..832926b27c92 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1327,8 +1327,6 @@ out:
if (msg->status && ctlr->handle_err)
ctlr->handle_err(ctlr, msg);
- spi_res_release(ctlr, msg);
-
spi_finalize_current_message(ctlr);
return ret;
@@ -1727,6 +1725,13 @@ 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) {