Date:   Mon, 27 Feb 2023 15:53:47 +0800
From:   Schspa Shi <schspa@...il.com>
To:     linux-kernel@...r.kernel.org, cocci@...ia.fr, peterz@...radead.org,
        mcgrof@...nel.org
Cc:     Schspa Shi <schspa@...il.com>,
        Julia Lawall <Julia.Lawall@...ia.fr>,
        Nicolas Palix <nicolas.palix@...g.fr>,
        Matthias Brugger <matthias.bgg@...il.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Ingo Molnar <mingo@...hat.com>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Valentin Schneider <vschneid@...hat.com>
Subject: [RFC PATCH] cocci: cpi: add complete api check script

When DECLARE_COMPLETION_ONSTACK was used, the user must to ensure the other
process won't reference the completion variable on stack. For a
killable/interruptiable version, we need extra code(add locks/use xchg) to
ensure this.

This patch provide a SmPL script to detect bad
DECLARE_COMPLETION_ONSTACK(_MAP) API usage, but far from perfect.

This is a common problem, and a lot of drivers have simpler problem. The
fellowing is a list of problems find by this SmPL patch, due to the complex
use of wait_for_complete* API, there will still be some false negatives and
false positives. This RFC patch is mainly used to discuss improvement
methods. If we introduce the wait_for_complete*_onstack API, it will be
easier to modify these problems, and the patch rules of SmPL will be very
easy. In the process of trying to write SmPL scripts, I strongly recommend
introducing two onstack APIs to complete this operation.

file:/Users/schspa/work/src/linux/drivers/infiniband/ulp/srpt/ib_srpt.c::2962 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/misc/tifm_7xx1.c::268 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/firmware/arm_scmi/driver.c::1001 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/video/fbdev/omap2/omapfb/dss/dispc-compat.c::595 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/video/fbdev/omap2/omapfb/dss/dispc-compat.c::491 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/video/fbdev/omap2/omapfb/dss/dispc-compat.c::538 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/video/fbdev/omap2/omapfb/dss/dispc-compat.c::645 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/video/fbdev/omap2/omapfb/dss/dsi.c::3175 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/video/fbdev/omap2/omapfb/dss/dsi.c::2360 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/video/fbdev/omap2/omapfb/dss/dsi.c::2314 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/video/fbdev/omap2/omapfb/dss/dsi.c::2634 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/gpu/drm/omapdrm/dss/dsi.c::1804 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/gpu/drm/omapdrm/dss/dsi.c::1758 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/gpu/drm/omapdrm/dss/dsi.c::2034 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/net/wireless/marvell/mwl8k.c::2259 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/net/wireless/mediatek/mt7601u/mcu.c::317 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/net/wireless/ti/wlcore/main.c::6674 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/net/wwan/t7xx/t7xx_state_monitor.c::416 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/soc/apple/rtkit.c::647 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/soc/apple/rtkit.c::653 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/soc/qcom/rpmh.c::269 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/aic94xx/aic94xx_tmf.c::339 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/snic/snic_ctl.c::242 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/snic/snic_scsi.c::1811 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/snic/snic_scsi.c::2266 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/snic/snic_scsi.c::1603 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/snic/snic_scsi.c::2073 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/qla2xxx/qla_os.c::1807 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/qla2xxx/qla_os.c::1328 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/ibmvscsi/ibmvfc.c::2466 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/aic7xxx/aic79xx_osm.c::844 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/aic7xxx/aic79xx_osm.c::2334 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/aic7xxx/aic7xxx_osm.c::2297 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/lpfc/lpfc_nvmet.c::2119 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/ipr.c::5153 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/scsi_error.c::1157 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/hisi_sas/hisi_sas_main.c::1215 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c::996 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c::867 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/isci/task.c::317 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/fnic/fnic_scsi.c::1844 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/fnic/fnic_scsi.c::2310 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/fnic/fnic_scsi.c::2086 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/scsi/fnic/fnic_scsi.c::2579 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/ufs/core/ufshcd.c::6752 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/ufs/core/ufshcd.c::4074 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/thunderbolt/ctl.c::604 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/i2c/busses/i2c-hisi.c::206 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/s390/cio/vfio_ccw_drv.c::71 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/slimbus/messaging.c::154 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/slimbus/qcom-ngd-ctrl.c::894 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/slimbus/qcom-ngd-ctrl.c::932 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/slimbus/qcom-ctrl.c::377 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/usb/core/devio.c::1142 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/usb/core/hcd.c::2229 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/spi/spi-hisi-sfc-v3xx.c::337 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/bluetooth/hci_bcm4377.c::955 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/i3c/master/mipi-i3c-hci/cmd_v1.c::336 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/i3c/master/mipi-i3c-hci/cmd_v2.c::278 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/i3c/master/mipi-i3c-hci/core.c::360 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/i3c/master/mipi-i3c-hci/core.c::312 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/i3c/master/mipi-i3c-hci/core.c::238 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/ata/libata-core.c::1558 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/w1/masters/ds1wm.c::285 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/w1/masters/ds1wm.c::233 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/drivers/w1/masters/ds1wm.c::262 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/lib/kunit/try-catch.c::76 was suspected to return a variable on stack
file:/Users/schspa/work/src/linux/sound/aoa/soundbus/i2sbus/pcm.c::264 was suspected to return a variable on stack

To fix this, we can add introducing two new API for this.

+
+void complete_on_stack(struct completion **x)
+{
+       struct completion *comp = xchg(*x, NULL);
+
+       if (comp)
+               complete(comp);
+}
+EXPORT_SYMBOL(complete_on_stack);
+
+int __sched wait_for_completion_state_on_stack(struct completion **x,
+                                       unsigned int state)
+{
+       struct completion *comp = *x;
+       int retval;
+
+       retval = wait_for_completion_state(comp, state);
+       if (retval) {
+               if (xchg(*x, NULL))
+                       return retval;
+
+               /*
+                * complete_on_stack will call complete shortly.
+                */
+               wait_for_completion(comp);
+       }
+
+       return retval;
+}
+EXPORT_SYMBOL(wait_for_completion_state_on_stack);

Link: https://lore.kernel.org/all/20221115140233.21981-1-schspa@gmail.com/T/#mf6a41a7009bb47af1b15adf2b7b355e495f609c4
Link: https://lore.kernel.org/all/7d1021f1-c88e-5a03-3b92-087f9be37491@I-love.SAKURA.ne.jp/

CC: Julia Lawall <Julia.Lawall@...ia.fr>
CC: Nicolas Palix <nicolas.palix@...g.fr>
CC: Matthias Brugger <matthias.bgg@...il.com>
CC: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
CC: Ingo Molnar <mingo@...hat.com>
CC: Peter Zijlstra <peterz@...radead.org>
CC: Juri Lelli <juri.lelli@...hat.com>
CC: Vincent Guittot <vincent.guittot@...aro.org>
CC: Dietmar Eggemann <dietmar.eggemann@....com>
CC: Steven Rostedt <rostedt@...dmis.org>
CC: Ben Segall <bsegall@...gle.com>
CC: Mel Gorman <mgorman@...e.de>
CC: Daniel Bristot de Oliveira <bristot@...hat.com>
CC: Valentin Schneider <vschneid@...hat.com>

Signed-off-by: Schspa Shi <schspa@...il.com>
---
 scripts/coccinelle/api/complete.cocci | 160 ++++++++++++++++++++++++++
 1 file changed, 160 insertions(+)
 create mode 100644 scripts/coccinelle/api/complete.cocci

diff --git a/scripts/coccinelle/api/complete.cocci b/scripts/coccinelle/api/complete.cocci
new file mode 100644
index 000000000000..d4cf32187180
--- /dev/null
+++ b/scripts/coccinelle/api/complete.cocci
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0
+///
+//  Copyright: (C) 2023 Schspa Shi.
+//  Confidence: High
+virtual report
+
+@r1 exists@
+declarer name DECLARE_COMPLETION_ONSTACK;
+declarer name DECLARE_COMPLETION_ONSTACK_MAP;
+position p;
+identifier done;
+identifier func;
+@@
+
+func(...) {
+...
+(
+DECLARE_COMPLETION_ONSTACK(done@p);
+|
+DECLARE_COMPLETION_ONSTACK_MAP(done@p, ...);
+)
+...
+}
+
+@...ked exists@
+identifier func=r1.func;
+identifier done=r1.done;
+position p1,p;
+@@
+
+func(...) {
+...
+(
+mutex_lock@p1
+|
+mutex_trylock@p1
+)
+ (...)
+...  when != mutex_unlock(...)
+done@p
+...
+}
+
+
+@...cked exists@
+identifier func=r1.func;
+identifier done=r1.done;
+position p1,p;
+expression e;
+@@
+
+func(...) {
+...
+e = &done;
+...
+(
+mutex_lock@p1
+|
+mutex_trylock@p1
+)
+ (...)
+...  when != mutex_unlock(...)
+e@p
+...
+}
+
+
+@..._wait_for_completion exists@
+position p;
+identifier done;
+identifier func=r1.func;
+identifier fb = { wait_for_completion, wait_for_completion_io};
+expression e;
+@@
+
+func(...) {
+...
+(
+...
+fb(&done@p);
+...
+|
+e = &done;
+...
+fb(e@p);
+)
+...
+}
+
+@..._while_wait exists@
+position p;
+identifier done, ret;
+identifier func=r1.func;
+identifier fb =~ "wait_for_completion.*";
+expression e;
+@@
+
+func(...) {
+...
+while (...) {
+	...
+	ret = fb(&done@p, e);
+	...
+}
+...
+}
+
+@..._while_wait2 exists@
+position p;
+identifier done;
+identifier func=r1.func;
+expression fb =~ "wait_for_completion.*";
+@@
+
+func(...) {
+...
+while (fb(&done@p, ...) == 0) {
+	...
+}
+...
+}
+
+
+@r2 depends on (!has_wait_for_completion && !has_while_wait && !has_while_wait2) exists@
+declarer name DECLARE_COMPLETION_ONSTACK;
+position p!={locked.p, elocked.p};
+identifier done=r1.done;
+identifier func=r1.func;
+expression e;
+@@
+
+func(...) {
+...
+(
+wait_for_completion_interruptible(&done@p)
+|
+wait_for_completion_killable(&done@p)
+|
+wait_for_completion_timeout(&done@p, ...)
+|
+wait_for_completion_io_timeout(&done@p, ...)
+|
+wait_for_completion_interruptible_timeout(&done@p, ...)
+|
+wait_for_completion_killable_timeout(&done@p, ...)
+|
+try_wait_for_completion(&done@p)
+|
+wait_for_completion_timeout(e@p, ...)
+)
+...
+}
+
+
+@...ipt:python depends on report@
+fp << r2.p;
+@@
+
+print('file:{:s}::{:s} was suspected to return a variable on stack'.format(fp[0].file, fp[0].line))
+
-- 
2.37.3

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