| Message ID | 20211208125220.v4.1.Iaac908f3e3149a89190ce006ba166e2d3fd247a3@changeid (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v4] rpmsg: char: Fix race between the release of rpmsg_ctrldev and cdev | expand |
Quoting Matthias Kaehlcke (2021-12-08 12:52:28) > From: Sujit Kautkar <sujitka@chromium.org> > > From: Sujit Kautkar <sujitka@chromium.org> This is here twice. Remove one? > > struct rpmsg_ctrldev contains a struct cdev. The current code frees > the rpmsg_ctrldev struct in rpmsg_ctrldev_release_device(), but the > cdev is a managed object, therefore its release is not predictable > and the rpmsg_ctrldev could be freed before the cdev is entirely > released, as in the backtrace below. > > [ 93.625603] ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x7c > [ 93.636115] WARNING: CPU: 0 PID: 12 at lib/debugobjects.c:488 debug_print_object+0x13c/0x1b0 > [ 93.644799] Modules linked in: veth xt_cgroup xt_MASQUERADE rfcomm algif_hash algif_skcipher af_alg uinput ip6table_nat fuse uvcvideo videobuf2_vmalloc venus_enc venus_dec videobuf2_dma_contig hci_uart btandroid btqca snd_soc_rt5682_i2c bluetooth qcom_spmi_temp_alarm snd_soc_rt5682v > [ 93.715175] CPU: 0 PID: 12 Comm: kworker/0:1 Tainted: G B 5.4.163-lockdep #26 > [ 93.723855] Hardware name: Google Lazor (rev3 - 8) with LTE (DT) > [ 93.730055] Workqueue: events kobject_delayed_cleanup > [ 93.735271] pstate: 60c00009 (nZCv daif +PAN +UAO) > [ 93.740216] pc : debug_print_object+0x13c/0x1b0 > [ 93.744890] lr : debug_print_object+0x13c/0x1b0 > [ 93.749555] sp : ffffffacf5bc7940 > [ 93.752978] x29: ffffffacf5bc7940 x28: dfffffd000000000 > [ 93.758448] x27: ffffffacdb11a800 x26: dfffffd000000000 > [ 93.763916] x25: ffffffd0734f856c x24: dfffffd000000000 > [ 93.769389] x23: 0000000000000000 x22: ffffffd0733c35b0 > [ 93.774860] x21: ffffffd0751994a0 x20: ffffffd075ec27c0 > [ 93.780338] x19: ffffffd075199100 x18: 00000000000276e0 > [ 93.785814] x17: 0000000000000000 x16: dfffffd000000000 > [ 93.791291] x15: ffffffffffffffff x14: 6e6968207473696c > [ 93.796768] x13: 0000000000000000 x12: ffffffd075e2b000 > [ 93.802244] x11: 0000000000000001 x10: 0000000000000000 > [ 93.807723] x9 : d13400dff1921900 x8 : d13400dff1921900 > [ 93.813200] x7 : 0000000000000000 x6 : 0000000000000000 > [ 93.818676] x5 : 0000000000000080 x4 : 0000000000000000 > [ 93.824152] x3 : ffffffd0732a0fa4 x2 : 0000000000000001 > [ 93.829628] x1 : ffffffacf5bc7580 x0 : 0000000000000061 > [ 93.835104] Call trace: > [ 93.837644] debug_print_object+0x13c/0x1b0 > [ 93.841963] __debug_check_no_obj_freed+0x25c/0x3c0 > [ 93.846987] debug_check_no_obj_freed+0x18/0x20 > [ 93.851669] slab_free_freelist_hook+0xbc/0x1e4 > [ 93.856346] kfree+0xfc/0x2f4 > [ 93.859416] rpmsg_ctrldev_release_device+0x78/0xb8 > [ 93.864445] device_release+0x84/0x168 > [ 93.868310] kobject_cleanup+0x12c/0x298 > [ 93.872356] kobject_delayed_cleanup+0x10/0x18 > [ 93.876948] process_one_work+0x578/0x92c > [ 93.881086] worker_thread+0x804/0xcf8 > [ 93.884963] kthread+0x2a8/0x314 > [ 93.888303] ret_from_fork+0x10/0x18 > > The cdev_device_add/del() API was created to address this issue > (see commit 233ed09d7fda), use it instead of cdev add/del(). > > Signed-off-by: Sujit Kautkar <sujitka@chromium.org> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org> > --- Reviewed-by: Stephen Boyd <swboyd@chromium.org>
On Wed, Dec 08, 2021 at 05:05:29PM -0800, Stephen Boyd wrote: > Quoting Matthias Kaehlcke (2021-12-08 12:52:28) > > From: Sujit Kautkar <sujitka@chromium.org> > > > > From: Sujit Kautkar <sujitka@chromium.org> > > This is here twice. Remove one? Ah, forgot that tools add that automatically and added a manual entry. Ohad/Bjorn/Mathieu: assuming there are no other comments, do you want me to resend this patch or can you remove the extra tag when applying it? > > struct rpmsg_ctrldev contains a struct cdev. The current code frees > > the rpmsg_ctrldev struct in rpmsg_ctrldev_release_device(), but the > > cdev is a managed object, therefore its release is not predictable > > and the rpmsg_ctrldev could be freed before the cdev is entirely > > released, as in the backtrace below. > > > > [ 93.625603] ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x7c > > [ 93.636115] WARNING: CPU: 0 PID: 12 at lib/debugobjects.c:488 debug_print_object+0x13c/0x1b0 > > [ 93.644799] Modules linked in: veth xt_cgroup xt_MASQUERADE rfcomm algif_hash algif_skcipher af_alg uinput ip6table_nat fuse uvcvideo videobuf2_vmalloc venus_enc venus_dec videobuf2_dma_contig hci_uart btandroid btqca snd_soc_rt5682_i2c bluetooth qcom_spmi_temp_alarm snd_soc_rt5682v > > [ 93.715175] CPU: 0 PID: 12 Comm: kworker/0:1 Tainted: G B 5.4.163-lockdep #26 > > [ 93.723855] Hardware name: Google Lazor (rev3 - 8) with LTE (DT) > > [ 93.730055] Workqueue: events kobject_delayed_cleanup > > [ 93.735271] pstate: 60c00009 (nZCv daif +PAN +UAO) > > [ 93.740216] pc : debug_print_object+0x13c/0x1b0 > > [ 93.744890] lr : debug_print_object+0x13c/0x1b0 > > [ 93.749555] sp : ffffffacf5bc7940 > > [ 93.752978] x29: ffffffacf5bc7940 x28: dfffffd000000000 > > [ 93.758448] x27: ffffffacdb11a800 x26: dfffffd000000000 > > [ 93.763916] x25: ffffffd0734f856c x24: dfffffd000000000 > > [ 93.769389] x23: 0000000000000000 x22: ffffffd0733c35b0 > > [ 93.774860] x21: ffffffd0751994a0 x20: ffffffd075ec27c0 > > [ 93.780338] x19: ffffffd075199100 x18: 00000000000276e0 > > [ 93.785814] x17: 0000000000000000 x16: dfffffd000000000 > > [ 93.791291] x15: ffffffffffffffff x14: 6e6968207473696c > > [ 93.796768] x13: 0000000000000000 x12: ffffffd075e2b000 > > [ 93.802244] x11: 0000000000000001 x10: 0000000000000000 > > [ 93.807723] x9 : d13400dff1921900 x8 : d13400dff1921900 > > [ 93.813200] x7 : 0000000000000000 x6 : 0000000000000000 > > [ 93.818676] x5 : 0000000000000080 x4 : 0000000000000000 > > [ 93.824152] x3 : ffffffd0732a0fa4 x2 : 0000000000000001 > > [ 93.829628] x1 : ffffffacf5bc7580 x0 : 0000000000000061 > > [ 93.835104] Call trace: > > [ 93.837644] debug_print_object+0x13c/0x1b0 > > [ 93.841963] __debug_check_no_obj_freed+0x25c/0x3c0 > > [ 93.846987] debug_check_no_obj_freed+0x18/0x20 > > [ 93.851669] slab_free_freelist_hook+0xbc/0x1e4 > > [ 93.856346] kfree+0xfc/0x2f4 > > [ 93.859416] rpmsg_ctrldev_release_device+0x78/0xb8 > > [ 93.864445] device_release+0x84/0x168 > > [ 93.868310] kobject_cleanup+0x12c/0x298 > > [ 93.872356] kobject_delayed_cleanup+0x10/0x18 > > [ 93.876948] process_one_work+0x578/0x92c > > [ 93.881086] worker_thread+0x804/0xcf8 > > [ 93.884963] kthread+0x2a8/0x314 > > [ 93.888303] ret_from_fork+0x10/0x18 > > > > The cdev_device_add/del() API was created to address this issue > > (see commit 233ed09d7fda), use it instead of cdev add/del(). > > > > Signed-off-by: Sujit Kautkar <sujitka@chromium.org> > > Signed-off-by: Matthias Kaehlcke <mka@chromium.org> > > --- > > Reviewed-by: Stephen Boyd <swboyd@chromium.org> Thanks!
On Wed, Dec 08, 2021 at 12:52:28PM -0800, Matthias Kaehlcke wrote: > From: Sujit Kautkar <sujitka@chromium.org> > > From: Sujit Kautkar <sujitka@chromium.org> > > struct rpmsg_ctrldev contains a struct cdev. The current code frees > the rpmsg_ctrldev struct in rpmsg_ctrldev_release_device(), but the > cdev is a managed object, therefore its release is not predictable > and the rpmsg_ctrldev could be freed before the cdev is entirely > released, as in the backtrace below. > > [ 93.625603] ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x7c > [ 93.636115] WARNING: CPU: 0 PID: 12 at lib/debugobjects.c:488 debug_print_object+0x13c/0x1b0 > [ 93.644799] Modules linked in: veth xt_cgroup xt_MASQUERADE rfcomm algif_hash algif_skcipher af_alg uinput ip6table_nat fuse uvcvideo videobuf2_vmalloc venus_enc venus_dec videobuf2_dma_contig hci_uart btandroid btqca snd_soc_rt5682_i2c bluetooth qcom_spmi_temp_alarm snd_soc_rt5682v > [ 93.715175] CPU: 0 PID: 12 Comm: kworker/0:1 Tainted: G B 5.4.163-lockdep #26 > [ 93.723855] Hardware name: Google Lazor (rev3 - 8) with LTE (DT) > [ 93.730055] Workqueue: events kobject_delayed_cleanup > [ 93.735271] pstate: 60c00009 (nZCv daif +PAN +UAO) > [ 93.740216] pc : debug_print_object+0x13c/0x1b0 > [ 93.744890] lr : debug_print_object+0x13c/0x1b0 > [ 93.749555] sp : ffffffacf5bc7940 > [ 93.752978] x29: ffffffacf5bc7940 x28: dfffffd000000000 > [ 93.758448] x27: ffffffacdb11a800 x26: dfffffd000000000 > [ 93.763916] x25: ffffffd0734f856c x24: dfffffd000000000 > [ 93.769389] x23: 0000000000000000 x22: ffffffd0733c35b0 > [ 93.774860] x21: ffffffd0751994a0 x20: ffffffd075ec27c0 > [ 93.780338] x19: ffffffd075199100 x18: 00000000000276e0 > [ 93.785814] x17: 0000000000000000 x16: dfffffd000000000 > [ 93.791291] x15: ffffffffffffffff x14: 6e6968207473696c > [ 93.796768] x13: 0000000000000000 x12: ffffffd075e2b000 > [ 93.802244] x11: 0000000000000001 x10: 0000000000000000 > [ 93.807723] x9 : d13400dff1921900 x8 : d13400dff1921900 > [ 93.813200] x7 : 0000000000000000 x6 : 0000000000000000 > [ 93.818676] x5 : 0000000000000080 x4 : 0000000000000000 > [ 93.824152] x3 : ffffffd0732a0fa4 x2 : 0000000000000001 > [ 93.829628] x1 : ffffffacf5bc7580 x0 : 0000000000000061 > [ 93.835104] Call trace: > [ 93.837644] debug_print_object+0x13c/0x1b0 > [ 93.841963] __debug_check_no_obj_freed+0x25c/0x3c0 > [ 93.846987] debug_check_no_obj_freed+0x18/0x20 > [ 93.851669] slab_free_freelist_hook+0xbc/0x1e4 > [ 93.856346] kfree+0xfc/0x2f4 > [ 93.859416] rpmsg_ctrldev_release_device+0x78/0xb8 > [ 93.864445] device_release+0x84/0x168 > [ 93.868310] kobject_cleanup+0x12c/0x298 > [ 93.872356] kobject_delayed_cleanup+0x10/0x18 > [ 93.876948] process_one_work+0x578/0x92c > [ 93.881086] worker_thread+0x804/0xcf8 > [ 93.884963] kthread+0x2a8/0x314 > [ 93.888303] ret_from_fork+0x10/0x18 > > The cdev_device_add/del() API was created to address this issue > (see commit 233ed09d7fda), use it instead of cdev add/del(). > > Signed-off-by: Sujit Kautkar <sujitka@chromium.org> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org> > --- > > Changes in v4: > - call cdev_device_del() from rpmsg_chrdev_remove() instead of > rpmsg_ctrldev_release_device() > - updated subject (was: "rpmsg: glink: Update cdev add/del API in > rpmsg_ctrldev_release_device()") > - updated commit message > - replaced backtrace in commit message with one that doesn't have > a dump_backtrace() call > > Changes in v3: > - Remove unecessary error check as per Matthias's comment > > Changes in v2: > - Fix typo in commit message > > drivers/rpmsg/rpmsg_char.c | 11 ++--------- > 1 file changed, 2 insertions(+), 9 deletions(-) > > diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c > index b5907b80727c..b1b75ef04560 100644 > --- a/drivers/rpmsg/rpmsg_char.c > +++ b/drivers/rpmsg/rpmsg_char.c > @@ -459,7 +459,6 @@ static void rpmsg_ctrldev_release_device(struct device *dev) > > ida_simple_remove(&rpmsg_ctrl_ida, dev->id); > ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt)); > - cdev_del(&ctrldev->cdev); > kfree(ctrldev); > } > > @@ -494,19 +493,13 @@ static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) > dev->id = ret; > dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret); > > - ret = cdev_add(&ctrldev->cdev, dev->devt, 1); > + ret = cdev_device_add(&ctrldev->cdev, &ctrldev->dev); > if (ret) > goto free_ctrl_ida; > > /* We can now rely on the release function for cleanup */ > dev->release = rpmsg_ctrldev_release_device; > > - ret = device_add(dev); > - if (ret) { > - dev_err(&rpdev->dev, "device_add failed: %d\n", ret); > - put_device(dev); > - } > - > dev_set_drvdata(&rpdev->dev, ctrldev); > > return ret; > @@ -532,7 +525,7 @@ static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev) > if (ret) > dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret); > > - device_del(&ctrldev->dev); > + cdev_device_del(&ctrldev->cdev, &ctrldev->dev); > put_device(&ctrldev->dev); Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> I'll let Bjorn pick this one to make sure it doesn't break anything for current users of the driver. Thanks, Mathieu > } > > -- > 2.34.1.400.ga245620fadb-goog >
On Mon, Dec 13, 2021 at 10:32:07AM -0700, Mathieu Poirier wrote: > On Wed, Dec 08, 2021 at 12:52:28PM -0800, Matthias Kaehlcke wrote: > > From: Sujit Kautkar <sujitka@chromium.org> > > > > From: Sujit Kautkar <sujitka@chromium.org> > > > > struct rpmsg_ctrldev contains a struct cdev. The current code frees > > the rpmsg_ctrldev struct in rpmsg_ctrldev_release_device(), but the > > cdev is a managed object, therefore its release is not predictable > > and the rpmsg_ctrldev could be freed before the cdev is entirely > > released, as in the backtrace below. > > > > [ 93.625603] ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x7c > > [ 93.636115] WARNING: CPU: 0 PID: 12 at lib/debugobjects.c:488 debug_print_object+0x13c/0x1b0 > > [ 93.644799] Modules linked in: veth xt_cgroup xt_MASQUERADE rfcomm algif_hash algif_skcipher af_alg uinput ip6table_nat fuse uvcvideo videobuf2_vmalloc venus_enc venus_dec videobuf2_dma_contig hci_uart btandroid btqca snd_soc_rt5682_i2c bluetooth qcom_spmi_temp_alarm snd_soc_rt5682v > > [ 93.715175] CPU: 0 PID: 12 Comm: kworker/0:1 Tainted: G B 5.4.163-lockdep #26 > > [ 93.723855] Hardware name: Google Lazor (rev3 - 8) with LTE (DT) > > [ 93.730055] Workqueue: events kobject_delayed_cleanup > > [ 93.735271] pstate: 60c00009 (nZCv daif +PAN +UAO) > > [ 93.740216] pc : debug_print_object+0x13c/0x1b0 > > [ 93.744890] lr : debug_print_object+0x13c/0x1b0 > > [ 93.749555] sp : ffffffacf5bc7940 > > [ 93.752978] x29: ffffffacf5bc7940 x28: dfffffd000000000 > > [ 93.758448] x27: ffffffacdb11a800 x26: dfffffd000000000 > > [ 93.763916] x25: ffffffd0734f856c x24: dfffffd000000000 > > [ 93.769389] x23: 0000000000000000 x22: ffffffd0733c35b0 > > [ 93.774860] x21: ffffffd0751994a0 x20: ffffffd075ec27c0 > > [ 93.780338] x19: ffffffd075199100 x18: 00000000000276e0 > > [ 93.785814] x17: 0000000000000000 x16: dfffffd000000000 > > [ 93.791291] x15: ffffffffffffffff x14: 6e6968207473696c > > [ 93.796768] x13: 0000000000000000 x12: ffffffd075e2b000 > > [ 93.802244] x11: 0000000000000001 x10: 0000000000000000 > > [ 93.807723] x9 : d13400dff1921900 x8 : d13400dff1921900 > > [ 93.813200] x7 : 0000000000000000 x6 : 0000000000000000 > > [ 93.818676] x5 : 0000000000000080 x4 : 0000000000000000 > > [ 93.824152] x3 : ffffffd0732a0fa4 x2 : 0000000000000001 > > [ 93.829628] x1 : ffffffacf5bc7580 x0 : 0000000000000061 > > [ 93.835104] Call trace: > > [ 93.837644] debug_print_object+0x13c/0x1b0 > > [ 93.841963] __debug_check_no_obj_freed+0x25c/0x3c0 > > [ 93.846987] debug_check_no_obj_freed+0x18/0x20 > > [ 93.851669] slab_free_freelist_hook+0xbc/0x1e4 > > [ 93.856346] kfree+0xfc/0x2f4 > > [ 93.859416] rpmsg_ctrldev_release_device+0x78/0xb8 > > [ 93.864445] device_release+0x84/0x168 > > [ 93.868310] kobject_cleanup+0x12c/0x298 > > [ 93.872356] kobject_delayed_cleanup+0x10/0x18 > > [ 93.876948] process_one_work+0x578/0x92c > > [ 93.881086] worker_thread+0x804/0xcf8 > > [ 93.884963] kthread+0x2a8/0x314 > > [ 93.888303] ret_from_fork+0x10/0x18 > > > > The cdev_device_add/del() API was created to address this issue > > (see commit 233ed09d7fda), use it instead of cdev add/del(). > > > > Signed-off-by: Sujit Kautkar <sujitka@chromium.org> > > Signed-off-by: Matthias Kaehlcke <mka@chromium.org> > > --- > > > > Changes in v4: > > - call cdev_device_del() from rpmsg_chrdev_remove() instead of > > rpmsg_ctrldev_release_device() > > - updated subject (was: "rpmsg: glink: Update cdev add/del API in > > rpmsg_ctrldev_release_device()") > > - updated commit message > > - replaced backtrace in commit message with one that doesn't have > > a dump_backtrace() call > > > > Changes in v3: > > - Remove unecessary error check as per Matthias's comment > > > > Changes in v2: > > - Fix typo in commit message > > > > drivers/rpmsg/rpmsg_char.c | 11 ++--------- > > 1 file changed, 2 insertions(+), 9 deletions(-) > > > > diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c > > index b5907b80727c..b1b75ef04560 100644 > > --- a/drivers/rpmsg/rpmsg_char.c > > +++ b/drivers/rpmsg/rpmsg_char.c > > @@ -459,7 +459,6 @@ static void rpmsg_ctrldev_release_device(struct device *dev) > > > > ida_simple_remove(&rpmsg_ctrl_ida, dev->id); > > ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt)); > > - cdev_del(&ctrldev->cdev); > > kfree(ctrldev); > > } > > > > @@ -494,19 +493,13 @@ static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) > > dev->id = ret; > > dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret); > > > > - ret = cdev_add(&ctrldev->cdev, dev->devt, 1); > > + ret = cdev_device_add(&ctrldev->cdev, &ctrldev->dev); > > if (ret) > > goto free_ctrl_ida; > > > > /* We can now rely on the release function for cleanup */ > > dev->release = rpmsg_ctrldev_release_device; > > > > - ret = device_add(dev); > > - if (ret) { > > - dev_err(&rpdev->dev, "device_add failed: %d\n", ret); > > - put_device(dev); > > - } > > - > > dev_set_drvdata(&rpdev->dev, ctrldev); > > > > return ret; > > @@ -532,7 +525,7 @@ static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev) > > if (ret) > > dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret); > > > > - device_del(&ctrldev->dev); > > + cdev_device_del(&ctrldev->cdev, &ctrldev->dev); > > put_device(&ctrldev->dev); > > Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> > > I'll let Bjorn pick this one to make sure it doesn't break anything for current > users of the driver. Bjorn: can this land or is there any action pending on my side?
On Fri 07 Jan 11:44 PST 2022, Matthias Kaehlcke wrote: > On Mon, Dec 13, 2021 at 10:32:07AM -0700, Mathieu Poirier wrote: > > On Wed, Dec 08, 2021 at 12:52:28PM -0800, Matthias Kaehlcke wrote: > > > From: Sujit Kautkar <sujitka@chromium.org> > > > > > > From: Sujit Kautkar <sujitka@chromium.org> > > > > > > struct rpmsg_ctrldev contains a struct cdev. The current code frees > > > the rpmsg_ctrldev struct in rpmsg_ctrldev_release_device(), but the > > > cdev is a managed object, therefore its release is not predictable > > > and the rpmsg_ctrldev could be freed before the cdev is entirely > > > released, as in the backtrace below. > > > > > > [ 93.625603] ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x7c > > > [ 93.636115] WARNING: CPU: 0 PID: 12 at lib/debugobjects.c:488 debug_print_object+0x13c/0x1b0 > > > [ 93.644799] Modules linked in: veth xt_cgroup xt_MASQUERADE rfcomm algif_hash algif_skcipher af_alg uinput ip6table_nat fuse uvcvideo videobuf2_vmalloc venus_enc venus_dec videobuf2_dma_contig hci_uart btandroid btqca snd_soc_rt5682_i2c bluetooth qcom_spmi_temp_alarm snd_soc_rt5682v > > > [ 93.715175] CPU: 0 PID: 12 Comm: kworker/0:1 Tainted: G B 5.4.163-lockdep #26 > > > [ 93.723855] Hardware name: Google Lazor (rev3 - 8) with LTE (DT) > > > [ 93.730055] Workqueue: events kobject_delayed_cleanup > > > [ 93.735271] pstate: 60c00009 (nZCv daif +PAN +UAO) > > > [ 93.740216] pc : debug_print_object+0x13c/0x1b0 > > > [ 93.744890] lr : debug_print_object+0x13c/0x1b0 > > > [ 93.749555] sp : ffffffacf5bc7940 > > > [ 93.752978] x29: ffffffacf5bc7940 x28: dfffffd000000000 > > > [ 93.758448] x27: ffffffacdb11a800 x26: dfffffd000000000 > > > [ 93.763916] x25: ffffffd0734f856c x24: dfffffd000000000 > > > [ 93.769389] x23: 0000000000000000 x22: ffffffd0733c35b0 > > > [ 93.774860] x21: ffffffd0751994a0 x20: ffffffd075ec27c0 > > > [ 93.780338] x19: ffffffd075199100 x18: 00000000000276e0 > > > [ 93.785814] x17: 0000000000000000 x16: dfffffd000000000 > > > [ 93.791291] x15: ffffffffffffffff x14: 6e6968207473696c > > > [ 93.796768] x13: 0000000000000000 x12: ffffffd075e2b000 > > > [ 93.802244] x11: 0000000000000001 x10: 0000000000000000 > > > [ 93.807723] x9 : d13400dff1921900 x8 : d13400dff1921900 > > > [ 93.813200] x7 : 0000000000000000 x6 : 0000000000000000 > > > [ 93.818676] x5 : 0000000000000080 x4 : 0000000000000000 > > > [ 93.824152] x3 : ffffffd0732a0fa4 x2 : 0000000000000001 > > > [ 93.829628] x1 : ffffffacf5bc7580 x0 : 0000000000000061 > > > [ 93.835104] Call trace: > > > [ 93.837644] debug_print_object+0x13c/0x1b0 > > > [ 93.841963] __debug_check_no_obj_freed+0x25c/0x3c0 > > > [ 93.846987] debug_check_no_obj_freed+0x18/0x20 > > > [ 93.851669] slab_free_freelist_hook+0xbc/0x1e4 > > > [ 93.856346] kfree+0xfc/0x2f4 > > > [ 93.859416] rpmsg_ctrldev_release_device+0x78/0xb8 > > > [ 93.864445] device_release+0x84/0x168 > > > [ 93.868310] kobject_cleanup+0x12c/0x298 > > > [ 93.872356] kobject_delayed_cleanup+0x10/0x18 > > > [ 93.876948] process_one_work+0x578/0x92c > > > [ 93.881086] worker_thread+0x804/0xcf8 > > > [ 93.884963] kthread+0x2a8/0x314 > > > [ 93.888303] ret_from_fork+0x10/0x18 > > > > > > The cdev_device_add/del() API was created to address this issue > > > (see commit 233ed09d7fda), use it instead of cdev add/del(). > > > > > > Signed-off-by: Sujit Kautkar <sujitka@chromium.org> > > > Signed-off-by: Matthias Kaehlcke <mka@chromium.org> > > > --- > > > > > > Changes in v4: > > > - call cdev_device_del() from rpmsg_chrdev_remove() instead of > > > rpmsg_ctrldev_release_device() > > > - updated subject (was: "rpmsg: glink: Update cdev add/del API in > > > rpmsg_ctrldev_release_device()") > > > - updated commit message > > > - replaced backtrace in commit message with one that doesn't have > > > a dump_backtrace() call > > > > > > Changes in v3: > > > - Remove unecessary error check as per Matthias's comment > > > > > > Changes in v2: > > > - Fix typo in commit message > > > > > > drivers/rpmsg/rpmsg_char.c | 11 ++--------- > > > 1 file changed, 2 insertions(+), 9 deletions(-) > > > > > > diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c > > > index b5907b80727c..b1b75ef04560 100644 > > > --- a/drivers/rpmsg/rpmsg_char.c > > > +++ b/drivers/rpmsg/rpmsg_char.c > > > @@ -459,7 +459,6 @@ static void rpmsg_ctrldev_release_device(struct device *dev) > > > > > > ida_simple_remove(&rpmsg_ctrl_ida, dev->id); > > > ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt)); > > > - cdev_del(&ctrldev->cdev); > > > kfree(ctrldev); > > > } > > > > > > @@ -494,19 +493,13 @@ static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) > > > dev->id = ret; > > > dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret); > > > > > > - ret = cdev_add(&ctrldev->cdev, dev->devt, 1); > > > + ret = cdev_device_add(&ctrldev->cdev, &ctrldev->dev); > > > if (ret) > > > goto free_ctrl_ida; > > > > > > /* We can now rely on the release function for cleanup */ > > > dev->release = rpmsg_ctrldev_release_device; > > > > > > - ret = device_add(dev); > > > - if (ret) { > > > - dev_err(&rpdev->dev, "device_add failed: %d\n", ret); > > > - put_device(dev); > > > - } > > > - > > > dev_set_drvdata(&rpdev->dev, ctrldev); > > > > > > return ret; > > > @@ -532,7 +525,7 @@ static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev) > > > if (ret) > > > dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret); > > > > > > - device_del(&ctrldev->dev); > > > + cdev_device_del(&ctrldev->cdev, &ctrldev->dev); > > > put_device(&ctrldev->dev); > > > > Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> > > > > I'll let Bjorn pick this one to make sure it doesn't break anything for current > > users of the driver. > > Bjorn: can this land or is there any action pending on my side? Thanks for the ping Mathieu, this looks good to me, so: Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> But it should come with: Fixes: c0cdc19f84a4 ("rpmsg: Driver for user space endpoint interface") But afaict we have the exact same problem in rpmsg_eptdev_create(), is there a reason why this isn't updated as well? Regards, Bjorn
On Fri, Jan 07, 2022 at 03:57:50PM -0800, Bjorn Andersson wrote: > On Fri 07 Jan 11:44 PST 2022, Matthias Kaehlcke wrote: > > > On Mon, Dec 13, 2021 at 10:32:07AM -0700, Mathieu Poirier wrote: > > > On Wed, Dec 08, 2021 at 12:52:28PM -0800, Matthias Kaehlcke wrote: > > > > From: Sujit Kautkar <sujitka@chromium.org> > > > > > > > > From: Sujit Kautkar <sujitka@chromium.org> > > > > > > > > struct rpmsg_ctrldev contains a struct cdev. The current code frees > > > > the rpmsg_ctrldev struct in rpmsg_ctrldev_release_device(), but the > > > > cdev is a managed object, therefore its release is not predictable > > > > and the rpmsg_ctrldev could be freed before the cdev is entirely > > > > released, as in the backtrace below. > > > > > > > > [ 93.625603] ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x7c > > > > [ 93.636115] WARNING: CPU: 0 PID: 12 at lib/debugobjects.c:488 debug_print_object+0x13c/0x1b0 > > > > [ 93.644799] Modules linked in: veth xt_cgroup xt_MASQUERADE rfcomm algif_hash algif_skcipher af_alg uinput ip6table_nat fuse uvcvideo videobuf2_vmalloc venus_enc venus_dec videobuf2_dma_contig hci_uart btandroid btqca snd_soc_rt5682_i2c bluetooth qcom_spmi_temp_alarm snd_soc_rt5682v > > > > [ 93.715175] CPU: 0 PID: 12 Comm: kworker/0:1 Tainted: G B 5.4.163-lockdep #26 > > > > [ 93.723855] Hardware name: Google Lazor (rev3 - 8) with LTE (DT) > > > > [ 93.730055] Workqueue: events kobject_delayed_cleanup > > > > [ 93.735271] pstate: 60c00009 (nZCv daif +PAN +UAO) > > > > [ 93.740216] pc : debug_print_object+0x13c/0x1b0 > > > > [ 93.744890] lr : debug_print_object+0x13c/0x1b0 > > > > [ 93.749555] sp : ffffffacf5bc7940 > > > > [ 93.752978] x29: ffffffacf5bc7940 x28: dfffffd000000000 > > > > [ 93.758448] x27: ffffffacdb11a800 x26: dfffffd000000000 > > > > [ 93.763916] x25: ffffffd0734f856c x24: dfffffd000000000 > > > > [ 93.769389] x23: 0000000000000000 x22: ffffffd0733c35b0 > > > > [ 93.774860] x21: ffffffd0751994a0 x20: ffffffd075ec27c0 > > > > [ 93.780338] x19: ffffffd075199100 x18: 00000000000276e0 > > > > [ 93.785814] x17: 0000000000000000 x16: dfffffd000000000 > > > > [ 93.791291] x15: ffffffffffffffff x14: 6e6968207473696c > > > > [ 93.796768] x13: 0000000000000000 x12: ffffffd075e2b000 > > > > [ 93.802244] x11: 0000000000000001 x10: 0000000000000000 > > > > [ 93.807723] x9 : d13400dff1921900 x8 : d13400dff1921900 > > > > [ 93.813200] x7 : 0000000000000000 x6 : 0000000000000000 > > > > [ 93.818676] x5 : 0000000000000080 x4 : 0000000000000000 > > > > [ 93.824152] x3 : ffffffd0732a0fa4 x2 : 0000000000000001 > > > > [ 93.829628] x1 : ffffffacf5bc7580 x0 : 0000000000000061 > > > > [ 93.835104] Call trace: > > > > [ 93.837644] debug_print_object+0x13c/0x1b0 > > > > [ 93.841963] __debug_check_no_obj_freed+0x25c/0x3c0 > > > > [ 93.846987] debug_check_no_obj_freed+0x18/0x20 > > > > [ 93.851669] slab_free_freelist_hook+0xbc/0x1e4 > > > > [ 93.856346] kfree+0xfc/0x2f4 > > > > [ 93.859416] rpmsg_ctrldev_release_device+0x78/0xb8 > > > > [ 93.864445] device_release+0x84/0x168 > > > > [ 93.868310] kobject_cleanup+0x12c/0x298 > > > > [ 93.872356] kobject_delayed_cleanup+0x10/0x18 > > > > [ 93.876948] process_one_work+0x578/0x92c > > > > [ 93.881086] worker_thread+0x804/0xcf8 > > > > [ 93.884963] kthread+0x2a8/0x314 > > > > [ 93.888303] ret_from_fork+0x10/0x18 > > > > > > > > The cdev_device_add/del() API was created to address this issue > > > > (see commit 233ed09d7fda), use it instead of cdev add/del(). > > > > > > > > Signed-off-by: Sujit Kautkar <sujitka@chromium.org> > > > > Signed-off-by: Matthias Kaehlcke <mka@chromium.org> > > > > --- > > > > > > > > Changes in v4: > > > > - call cdev_device_del() from rpmsg_chrdev_remove() instead of > > > > rpmsg_ctrldev_release_device() > > > > - updated subject (was: "rpmsg: glink: Update cdev add/del API in > > > > rpmsg_ctrldev_release_device()") > > > > - updated commit message > > > > - replaced backtrace in commit message with one that doesn't have > > > > a dump_backtrace() call > > > > > > > > Changes in v3: > > > > - Remove unecessary error check as per Matthias's comment > > > > > > > > Changes in v2: > > > > - Fix typo in commit message > > > > > > > > drivers/rpmsg/rpmsg_char.c | 11 ++--------- > > > > 1 file changed, 2 insertions(+), 9 deletions(-) > > > > > > > > diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c > > > > index b5907b80727c..b1b75ef04560 100644 > > > > --- a/drivers/rpmsg/rpmsg_char.c > > > > +++ b/drivers/rpmsg/rpmsg_char.c > > > > @@ -459,7 +459,6 @@ static void rpmsg_ctrldev_release_device(struct device *dev) > > > > > > > > ida_simple_remove(&rpmsg_ctrl_ida, dev->id); > > > > ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt)); > > > > - cdev_del(&ctrldev->cdev); > > > > kfree(ctrldev); > > > > } > > > > > > > > @@ -494,19 +493,13 @@ static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) > > > > dev->id = ret; > > > > dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret); > > > > > > > > - ret = cdev_add(&ctrldev->cdev, dev->devt, 1); > > > > + ret = cdev_device_add(&ctrldev->cdev, &ctrldev->dev); > > > > if (ret) > > > > goto free_ctrl_ida; > > > > > > > > /* We can now rely on the release function for cleanup */ > > > > dev->release = rpmsg_ctrldev_release_device; > > > > > > > > - ret = device_add(dev); > > > > - if (ret) { > > > > - dev_err(&rpdev->dev, "device_add failed: %d\n", ret); > > > > - put_device(dev); > > > > - } > > > > - > > > > dev_set_drvdata(&rpdev->dev, ctrldev); > > > > > > > > return ret; > > > > @@ -532,7 +525,7 @@ static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev) > > > > if (ret) > > > > dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret); > > > > > > > > - device_del(&ctrldev->dev); > > > > + cdev_device_del(&ctrldev->cdev, &ctrldev->dev); > > > > put_device(&ctrldev->dev); > > > > > > Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> > > > > > > I'll let Bjorn pick this one to make sure it doesn't break anything for current > > > users of the driver. > > > > Bjorn: can this land or is there any action pending on my side? > > Thanks for the ping Mathieu, this looks good to me, so: > > Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> > > But it should come with: > > Fixes: c0cdc19f84a4 ("rpmsg: Driver for user space endpoint interface") Thanks, will add! > But afaict we have the exact same problem in rpmsg_eptdev_create(), is > there a reason why this isn't updated as well? Because I didn't notice :) I'll fix it too, not sure yet if in the same patch or a separate one.
diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c index b5907b80727c..b1b75ef04560 100644 --- a/drivers/rpmsg/rpmsg_char.c +++ b/drivers/rpmsg/rpmsg_char.c @@ -459,7 +459,6 @@ static void rpmsg_ctrldev_release_device(struct device *dev) ida_simple_remove(&rpmsg_ctrl_ida, dev->id); ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt)); - cdev_del(&ctrldev->cdev); kfree(ctrldev); } @@ -494,19 +493,13 @@ static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) dev->id = ret; dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret); - ret = cdev_add(&ctrldev->cdev, dev->devt, 1); + ret = cdev_device_add(&ctrldev->cdev, &ctrldev->dev); if (ret) goto free_ctrl_ida; /* We can now rely on the release function for cleanup */ dev->release = rpmsg_ctrldev_release_device; - ret = device_add(dev); - if (ret) { - dev_err(&rpdev->dev, "device_add failed: %d\n", ret); - put_device(dev); - } - dev_set_drvdata(&rpdev->dev, ctrldev); return ret; @@ -532,7 +525,7 @@ static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev) if (ret) dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret); - device_del(&ctrldev->dev); + cdev_device_del(&ctrldev->cdev, &ctrldev->dev); put_device(&ctrldev->dev); }