git: 18679ab1c065 - main - mmc_sim: fix setting of the mutex name

The branch main has been updated by avg:

URL: https://cgit.FreeBSD.org/src/commit/?id=18679ab1c06575517df9df2509564dbf038d4720

commit 18679ab1c06575517df9df2509564dbf038d4720
Author:     Andriy Gapon <avg@FreeBSD.org>
AuthorDate: 2021-12-15 11:37:59 +0000
Commit:     Andriy Gapon <avg@FreeBSD.org>
CommitDate: 2021-12-15 11:42:02 +0000

    mmc_sim: fix setting of the mutex name
    
    To quote the manual:
     The pointer passed in as name and type is saved rather than the data
     it points to.  The data pointed to must remain stable until the mutex
     is destroyed.
    
    It seems that the type is actually copied, but the name is stored as
    a pointer indeed.
    mmc_cam_sim_alloc used a name stored on stack.
    So, a corrupt mutex name would be reported.
    For example:
      lock order reversal: (sleepable after non-sleepable)
      1st 0xd7285b20 <8A><C0><C0>P@<C1><D0>P@<C1>^D^A (aw_mmc_sim, sleep mutex) @ sys/cam/cam_xpt.c:2804
    
    This change moves the name to struct mmc_sim.
    Also, that name is used as the sim name as well.
    Unused mtx_name variable is removed too.
    The name buffer is reduced to 16 characters.
    
    Reviewed by:    manu, bz
    MFC after:      10 days
    Differential Revision:  https://reviews.freebsd.org/D33412
---
 sys/cam/mmc/mmc_sim.c | 9 +++------
 sys/cam/mmc/mmc_sim.h | 1 +
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/sys/cam/mmc/mmc_sim.c b/sys/cam/mmc/mmc_sim.c
index 45d706f61d0a..792551a93511 100644
--- a/sys/cam/mmc/mmc_sim.c
+++ b/sys/cam/mmc/mmc_sim.c
@@ -191,7 +191,6 @@ mmc_cam_sim_default_action(struct cam_sim *sim, union ccb *ccb)
 int
 mmc_cam_sim_alloc(device_t dev, const char *name, struct mmc_sim *mmc_sim)
 {
-	char sim_name[64], mtx_name[64];
 
 	mmc_sim->dev = dev;
 
@@ -199,13 +198,11 @@ mmc_cam_sim_alloc(device_t dev, const char *name, struct mmc_sim *mmc_sim)
 		goto fail;
 	}
 
-	snprintf(sim_name, sizeof(sim_name), "%s_sim", name);
-	snprintf(mtx_name, sizeof(mtx_name), "%s_mtx", name);
-
-	mtx_init(&mmc_sim->mtx, sim_name, NULL, MTX_DEF);
+	snprintf(mmc_sim->name, sizeof(mmc_sim->name), "%s_sim", name);
+	mtx_init(&mmc_sim->mtx, mmc_sim->name, NULL, MTX_DEF);
 	mmc_sim->sim = cam_sim_alloc(mmc_cam_sim_default_action,
 	    mmc_cam_default_poll,
-	    name, mmc_sim, device_get_unit(dev),
+	    mmc_sim->name, mmc_sim, device_get_unit(dev),
 	    &mmc_sim->mtx, 1, 1, mmc_sim->devq);
 
 	if (mmc_sim->sim == NULL) {
diff --git a/sys/cam/mmc/mmc_sim.h b/sys/cam/mmc/mmc_sim.h
index 2b1159a9758e..10bd183c307d 100644
--- a/sys/cam/mmc/mmc_sim.h
+++ b/sys/cam/mmc/mmc_sim.h
@@ -33,6 +33,7 @@
 struct mmc_sim {
 	struct mmc_cam_sim_softc	*sc;
 	struct mtx			mtx;
+	char				name[64];
 	struct cam_devq			*devq;
 	struct cam_sim			*sim;
 	device_t			dev;