Messages in this thread | | | Date | Thu, 21 Sep 2023 15:07:05 +0200 | Subject | Re: [PATCH v7 45/49] media: core: Add bitmap manage bufs array entries | From | Benjamin Gaignard <> |
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Le 21/09/2023 à 14:46, Benjamin Gaignard a écrit : > > Le 21/09/2023 à 14:13, Hans Verkuil a écrit : >> On 21/09/2023 14:05, Benjamin Gaignard wrote: >>> Le 21/09/2023 à 12:24, Hans Verkuil a écrit : >>>> On 21/09/2023 11:28, Benjamin Gaignard wrote: >>>>> Le 20/09/2023 à 16:56, Hans Verkuil a écrit : >>>>>> On 20/09/2023 16:30, Benjamin Gaignard wrote: >>>>>> <snip> >>>>>> >>>>>>>>> num_buffers = min_t(unsigned int, num_buffers, >>>>>>>>> q->max_allowed_buffers - >>>>>>>>> vb2_get_num_buffers(q)); >>>>>>>>> - first_index = vb2_get_num_buffers(q); >>>>>>>>> + first_index = bitmap_find_next_zero_area(q->bufs_map, >>>>>>>>> q->max_allowed_buffers, >>>>>>>>> + 0, num_buffers, 0); >>>>>>>>> if (first_index >= q->max_allowed_buffers) >>>>>>>>> return 0; >>>>>>>>> @@ -675,7 +678,13 @@ static void __vb2_queue_free(struct >>>>>>>>> vb2_queue *q, unsigned int buffers) >>>>>>>>> struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q, >>>>>>>>> unsigned int index) >>>>>>>>> { >>>>>>>>> - if (index < q->num_buffers) >>>>>>>>> + if (!q->bufs_map || !q->bufs) >>>>>>>>> + return NULL; >>>>>>>> I don't think this can ever happen. >>>>>>> I got kernel crash without them. >>>>>>> I will keep them. >>>>>> What is the backtrace? How can this happen? It feels wrong that >>>>>> this can be >>>>>> called with a vb2_queue that apparently is not properly initialized. >>>>> I have this log when adding dump_stack() in vb2_get_buffer() if >>>>> !q->bufs_bitmap: >>>>> >>>>> [ 18.924627] Call trace: >>>>> [ 18.927090] dump_backtrace+0x94/0xec >>>>> [ 18.930787] show_stack+0x18/0x24 >>>>> [ 18.934137] dump_stack_lvl+0x48/0x60 >>>>> [ 18.937833] dump_stack+0x18/0x24 >>>>> [ 18.941166] __vb2_queue_cancel+0x23c/0x2f0 >>>>> [ 18.945365] vb2_core_queue_release+0x24/0x6c >>>>> [ 18.949740] vb2_queue_release+0x10/0x1c >>>>> [ 18.953677] v4l2_m2m_ctx_release+0x20/0x40 >>>>> [ 18.957892] hantro_release+0x20/0x54 >>>>> [ 18.961584] v4l2_release+0x74/0xec >>>>> [ 18.965110] __fput+0xb4/0x274 >>>>> [ 18.968205] __fput_sync+0x50/0x5c >>>>> [ 18.971626] __arm64_sys_close+0x38/0x7c >>>>> [ 18.975562] invoke_syscall+0x48/0x114 >>>>> [ 18.979329] el0_svc_common.constprop.0+0xc0/0xe0 >>>>> [ 18.984068] do_el0_svc+0x1c/0x28 >>>>> [ 18.987402] el0_svc+0x40/0xe8 >>>>> [ 18.990470] el0t_64_sync_handler+0x100/0x12c >>>>> [ 18.994842] el0t_64_sync+0x190/0x194 >>>>> >>>>> This happen at boot time when hantro driver is open and close >>>>> without other actions. >>>> Ah, now I see the problem. q->bufs and q->bufs_map are allocated in >>>> vb2_core_create_bufs and vb2_core_reqbufs, but they should be >>>> allocated >>>> in vb2_queue_init: that's the counterpart of vb2_core_queue_release.
Hans, I think we are doing loops in your comment :-) https://patchwork.kernel.org/comment/25496456/
Regards, Benjamin
>>>> >>>> With that change you shouldn't have to check for q->bufs/bufs_map >>>> anymore. >>> It is a better solution but even like this vb2_core_queue_release() >>> is called >>> at least 2 times on the same vivid queue and without testing >>> q->bufs_bitmap >>> makes kernel crash. >> Do you have a stacktrace for that? Perhaps vb2_core_queue_release >> should check >> for q->bufs/q->bufs_map and return if those are NULL. But it could >> also be a >> bug that it is called twice, it just was never noticed because it was >> harmless >> before. > > I have added some printk to log that when running test-media on vivid: > > [ 130.497426] vb2_core_queue_init queue cap-0000000050d195ab allocate > q->bufs 00000000dc2c15ed and q->bufs_bitmap 000000008173fc5a > ... > [ 130.733967] vb2_core_queue_release queue cap-0000000050d195ab > release q->bufs and q->bufs_bitmap > [ 133.866345] vb2_get_buffer queue cap-0000000050d195ab > q->bufs_bitmap is NULL > [ 133.873454] CPU: 1 PID: 321 Comm: v4l2-ctl Not tainted 6.6.0-rc1+ #542 > [ 133.879997] Hardware name: NXP i.MX8MQ EVK (DT) > [ 133.884536] Call trace: > [ 133.886988] dump_backtrace+0x94/0xec > [ 133.890673] show_stack+0x18/0x24 > [ 133.894002] dump_stack_lvl+0x48/0x60 > [ 133.897681] dump_stack+0x18/0x24 > [ 133.901009] __vb2_queue_cancel+0x250/0x31c > [ 133.905209] vb2_core_queue_release+0x24/0x88 > [ 133.909580] _vb2_fop_release+0xb0/0xbc > [ 133.913428] vb2_fop_release+0x2c/0x58 > [ 133.917187] vivid_fop_release+0x80/0x388 [vivid] > [ 133.921948] v4l2_release+0x74/0xec > [ 133.925452] __fput+0xb4/0x274 > [ 133.928520] __fput_sync+0x50/0x5c > [ 133.931934] __arm64_sys_close+0x38/0x7c > [ 133.935868] invoke_syscall+0x48/0x114 > [ 133.939630] el0_svc_common.constprop.0+0x40/0xe0 > [ 133.944349] do_el0_svc+0x1c/0x28 > [ 133.947677] el0_svc+0x40/0xe8 > [ 133.950741] el0t_64_sync_handler+0x100/0x12c > [ 133.955109] el0t_64_sync+0x190/0x194 > > and later I have a call to reqbufs on the same queue without call to > vb2_core_queue_init before > > [ 58.696812] __vb2_queue_alloc queue cap- > 0000000050d195abq->bufs_bitmap is NULL > [ 58.704148] CPU: 1 PID: 319 Comm: v4l2-compliance Not tainted > 6.6.0-rc1+ #544 > [ 58.711291] Hardware name: NXP i.MX8MQ EVK (DT) > [ 58.715826] Call trace: > [ 58.718274] dump_backtrace+0x94/0xec > [ 58.721951] show_stack+0x18/0x24 > [ 58.725274] dump_stack_lvl+0x48/0x60 > [ 58.728946] dump_stack+0x18/0x24 > [ 58.732268] __vb2_queue_alloc+0x4a8/0x50c > [ 58.736374] vb2_core_reqbufs+0x274/0x46c > [ 58.740391] vb2_ioctl_reqbufs+0xb0/0xe8 > [ 58.744320] vidioc_reqbufs+0x50/0x64 [vivid] > [ 58.748717] v4l_reqbufs+0x50/0x64 > [ 58.752125] __video_do_ioctl+0x164/0x3c8 > [ 58.756140] video_usercopy+0x200/0x668 > [ 58.759982] video_ioctl2+0x18/0x28 > [ 58.763475] v4l2_ioctl+0x40/0x60 > [ 58.766798] __arm64_sys_ioctl+0xac/0xf0 > [ 58.770730] invoke_syscall+0x48/0x114 > [ 58.774487] el0_svc_common.constprop.0+0x40/0xe0 > [ 58.779199] do_el0_svc+0x1c/0x28 > [ 58.782520] el0_svc+0x40/0xe8 > [ 58.785580] el0t_64_sync_handler+0x100/0x12c > [ 58.789942] el0t_64_sync+0x190/0x194 > >> >> Regards, >> >> Hans >> >>>> Regards, >>>> >>>> Hans >>>> >>>>>>>>> + >>>>>>>>> + return (bitmap_weight(q->bufs_map, >>>>>>>>> q->max_allowed_buffers) > 0); >>>>>>>> How about: >>>>>>>> >>>>>>>> return vb2_get_num_buffers(q) > 0; >>>>>>> vb2_get_num_buffers is defined in videobuf2-core.c, I'm not sure >>>>>>> that >>>>>>> an inline function could depend of a module function. >>>>>> Not a problem. E.g. v4l2-ctrls.h is full of such static inlines. >>>>>> >>>>>> Regards, >>>>>> >>>>>> Hans >>>>>> >>
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