Linux kernel stable tree (mirror) https://git.radix-linux.su/kernel/linux.git/atom?h=v6.19.11 2022-06-14T22:41:10+00:00 2022-06-14T22:41:10+00:00 AngeloGioacchino Del Regno angelogioacchino.delregno@collabora.com 2022-05-25T09:12:01+00:00 urn:sha1:353d9214682e65c55cdffad8c82139a3321c5f13 During execution of the worker that's used to register rpmsg devices we are safely locking the channels mutex but, when creating a new endpoint for such devices, we are registering a IPI on the SCP, which then makes the SCP to trigger an interrupt, lock its own mutex and in turn register more subdevices. This creates a circular locking dependency situation, as the mtk_rpmsg channels_lock will then depend on the SCP IPI lock. [ 15.447736] ====================================================== [ 15.460158] WARNING: possible circular locking dependency detected [ 15.460161] 5.17.0-next-20220324+ #399 Not tainted [ 15.460165] ------------------------------------------------------ [ 15.460166] kworker/0:3/155 is trying to acquire lock: [ 15.460170] ffff5b4d0eaf1308 (&scp->ipi_desc[i].lock){+.+.}-{4:4}, at: scp_ipi_lock+0x34/0x50 [mtk_scp_ipi] [ 15.504958] [] but task is already holding lock: [ 15.504960] ffff5b4d0e8f1918 (&mtk_subdev->channels_lock){+.+.}-{4:4}, at: mtk_register_device_work_function+0x50/0x1cc [mtk_rpmsg] [ 15.504978] [] which lock already depends on the new lock. [ 15.504980] [] the existing dependency chain (in reverse order) is: [ 15.504982] [] -> #1 (&mtk_subdev->channels_lock){+.+.}-{4:4}: [ 15.504990] lock_acquire+0x68/0x84 [ 15.504999] __mutex_lock+0xa4/0x3e0 [ 15.505007] mutex_lock_nested+0x40/0x70 [ 15.505012] mtk_rpmsg_ns_cb+0xe4/0x134 [mtk_rpmsg] [ 15.641684] mtk_rpmsg_ipi_handler+0x38/0x64 [mtk_rpmsg] [ 15.641693] scp_ipi_handler+0xbc/0x180 [mtk_scp] [ 15.663905] mt8192_scp_irq_handler+0x44/0xa4 [mtk_scp] [ 15.663915] scp_irq_handler+0x6c/0xa0 [mtk_scp] [ 15.685779] irq_thread_fn+0x34/0xa0 [ 15.685785] irq_thread+0x18c/0x240 [ 15.685789] kthread+0x104/0x110 [ 15.709579] ret_from_fork+0x10/0x20 [ 15.709586] [] -> #0 (&scp->ipi_desc[i].lock){+.+.}-{4:4}: [ 15.731271] __lock_acquire+0x11e4/0x1910 [ 15.740367] lock_acquire.part.0+0xd8/0x220 [ 15.749813] lock_acquire+0x68/0x84 [ 15.757861] __mutex_lock+0xa4/0x3e0 [ 15.766084] mutex_lock_nested+0x40/0x70 [ 15.775006] scp_ipi_lock+0x34/0x50 [mtk_scp_ipi] [ 15.785503] scp_ipi_register+0x40/0xa4 [mtk_scp_ipi] [ 15.796697] scp_register_ipi+0x1c/0x30 [mtk_scp] [ 15.807194] mtk_rpmsg_create_ept+0xa0/0x108 [mtk_rpmsg] [ 15.818912] rpmsg_create_ept+0x44/0x60 [ 15.827660] cros_ec_rpmsg_probe+0x15c/0x1f0 [ 15.837282] rpmsg_dev_probe+0x128/0x1d0 [ 15.846203] really_probe.part.0+0xa4/0x2a0 [ 15.855649] __driver_probe_device+0xa0/0x150 [ 15.865443] driver_probe_device+0x48/0x150 [ 15.877157] __device_attach_driver+0xc0/0x12c [ 15.889359] bus_for_each_drv+0x80/0xe0 [ 15.900330] __device_attach+0xe4/0x190 [ 15.911303] device_initial_probe+0x1c/0x2c [ 15.922969] bus_probe_device+0xa8/0xb0 [ 15.933927] device_add+0x3a8/0x8a0 [ 15.944193] device_register+0x28/0x40 [ 15.954970] rpmsg_register_device+0x5c/0xa0 [ 15.966782] mtk_register_device_work_function+0x148/0x1cc [mtk_rpmsg] [ 15.983146] process_one_work+0x294/0x664 [ 15.994458] worker_thread+0x7c/0x45c [ 16.005069] kthread+0x104/0x110 [ 16.014789] ret_from_fork+0x10/0x20 [ 16.025201] [] other info that might help us debug this: [ 16.047769] Possible unsafe locking scenario: [ 16.063942] CPU0 CPU1 [ 16.075166] ---- ---- [ 16.086376] lock(&mtk_subdev->channels_lock); [ 16.097592] lock(&scp->ipi_desc[i].lock); [ 16.113188] lock(&mtk_subdev->channels_lock); [ 16.129482] lock(&scp->ipi_desc[i].lock); [ 16.140020] [] *** DEADLOCK *** [ 16.158282] 4 locks held by kworker/0:3/155: [ 16.168978] #0: ffff5b4d00008748 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1fc/0x664 [ 16.190017] #1: ffff80000953bdc8 ((work_completion)(&mtk_subdev->register_work)){+.+.}-{0:0}, at: process_one_work+0x1fc/0x664 [ 16.215269] #2: ffff5b4d0e8f1918 (&mtk_subdev->channels_lock){+.+.}-{4:4}, at: mtk_register_device_work_function+0x50/0x1cc [mtk_rpmsg] [ 16.242131] #3: ffff5b4d05964190 (&dev->mutex){....}-{4:4}, at: __device_attach+0x44/0x190 To solve this, simply unlock the channels_lock mutex before calling mtk_rpmsg_register_device() and relock it right after, as safety is still ensured by the locking mechanism that happens right after through SCP. Fixes: 7017996951fd ("rpmsg: add rpmsg support for mt8183 SCP.") Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> Link: https://lore.kernel.org/r/20220525091201.14210-1-angelogioacchino.delregno@collabora.com Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> 2021-09-27T23:32:06+00:00 Tinghan Shen tinghan.shen@mediatek.com 2021-09-24T03:39:34+00:00 urn:sha1:54c9237a97e00e506ed18e89b12690a9ddfe4a56 Change from "mtk,rpmsg-name" to "mediatek,rpmsg-name" to sync with the vendor name defined in vendor-prefixes.yaml. Signed-off-by: Tinghan Shen <tinghan.shen@mediatek.com> Link: https://lore.kernel.org/r/20210924033935.2127-6-tinghan.shen@mediatek.com [Fixed capital letter in title] Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> 2020-09-15T03:43:24+00:00 Nicolas Boichat drinkcat@chromium.org 2020-09-03T00:05:58+00:00 urn:sha1:231331b2dbd71487159a0400d9ffd967eb0d0e08 If rpmsg_register_device fails, it will call mtk_rpmsg_release_device which already frees mdev. Fixes: 7017996951fd ("rpmsg: add rpmsg support for mt8183 SCP.") Signed-off-by: Nicolas Boichat <drinkcat@chromium.org> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> Link: https://lore.kernel.org/r/20200903080547.v3.1.I56cf27cd59f4013bd074dc622c8b8248b034a4cc@changeid Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> 2020-04-17T10:05:29+00:00 Michael S. Tsirkin mst@redhat.com 2020-04-09T21:09:35+00:00 urn:sha1:3d820cd4e82d1ff74340053fed54c6b89c8cc02b In preparation to virtio header changes, include slab.h directly as this module is using it. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> 2020-01-20T18:29:56+00:00 Pi-Hsun Shih pihsun@chromium.org 2019-11-12T11:03:26+00:00 urn:sha1:7017996951fde84698ddfe7fd47f92bd9d9eb85d Add a simple rpmsg support for mt8183 SCP, that use IPI / IPC directly. Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org> Link: https://lore.kernel.org/r/20191112110330.179649-4-pihsun@chromium.org Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>