Re: [PATCH v2 6/8] media: platform: amd: isp4 video node and buffers handling added

Sultan Alsawaf
2025-08-11T06:02:05Z

On Wed, Jul 30, 2025 at 05:34:22PM -0700, Sultan Alsawaf wrote:
> On Tue, Jul 29, 2025 at 03:43:14PM +0800, Du, Bin wrote:
> > Hi Sultan, really appreciate your time and effort
> >
> > On 7/28/2025 3:04 PM, Sultan Alsawaf wrote:
> > > I found more refcounting issues in addition to the ones from my other emails
> > > while trying to make my webcam work:
> > >
> > > On Wed, Jun 18, 2025 at 05:19:57PM +0800, Bin Du wrote:
> > > > +static int isp4vid_vb2_mmap(void *buf_priv, struct vm_area_struct *vma)
> > > > +{
> > > > + struct isp4vid_vb2_buf *buf = buf_priv;
> > > > + int ret;
> > > > +
> > > > + if (!buf) {
> > > > + pr_err("fail no memory to map\n");
> > > > + return -EINVAL;
> > > > + }
> > > > +
> > > > + ret = remap_vmalloc_range(vma, buf->vaddr, 0);
> > > > + if (ret) {
> > > > + dev_err(buf->dev, "fail remap vmalloc mem, %d\n", ret);
> > > > + return ret;
> > > > + }
> > > > +
> > > > + /*
> > > > + * Make sure that vm_areas for 2 buffers won't be merged together
> > > > + */
> > > > + vm_flags_set(vma, VM_DONTEXPAND);
> > > > +
> > > > + dev_dbg(buf->dev, "mmap isp user bo 0x%llx size %ld refcount %d\n",
> > > > + buf->gpu_addr, buf->size, buf->refcount.refs.counter);
> > >
> > > Use refcount_read() instead of reading the refcount's atomic_t counter directly.
> > > This is done in 3 other places; change those to refcount_read() as well.
> > >
> > > This didn't cause any functional problems, but it should still be fixed.
> > >
> > > > +
> > > > + return 0;
> > > > +}
> > >
> > Sure, will fix it
> >
> > > [snip]
> > >
> > > > +static void isp4vid_vb2_detach_dmabuf(void *mem_priv)
> > > > +{
> > > > + struct isp4vid_vb2_buf *buf = mem_priv;
> > > > +
> > > > + if (!buf) {
> > > > + pr_err("fail invalid buf handle\n");
> > > > + return;
> > > > + }
> > > > +
> > > > + struct iosys_map map = IOSYS_MAP_INIT_VADDR(buf->vaddr);
> > > > +
> > > > + dev_dbg(buf->dev, "detach dmabuf of isp user bo 0x%llx size %ld",
> > > > + buf->gpu_addr, buf->size);
> > > > +
> > > > + if (buf->vaddr)
> > > > + dma_buf_vunmap_unlocked(buf->dbuf, &map);
> > > > +
> > > > + // put dmabuf for exported ones
> > > > + dma_buf_put(buf->dbuf);
> > > > +
> > > > + kfree(buf);
> > > > +}
> > >
> > > As mentioned in the other email, the dma_buf_put() here needs to be removed. But
> > > that's not all: the dma_buf_vunmap_unlocked() needs to be removed too because
> > > vb2 will always unmap the buffer before detaching it. As a result, having the
> > > dma_buf_vunmap_unlocked() call here results in a use-after-free when vb2 calls
> > > the unmap_dmabuf memop.
> > >
> > > Change this function to the following:
> > >
> > > static void isp4vid_vb2_detach_dmabuf(void *mem_priv)
> > > {
> > > struct isp4vid_vb2_buf *buf = mem_priv;
> > >
> > > kfree(buf);
> > > }
> > >
> > Will have a try
> >
> > > > +static void isp4vid_qops_buffer_cleanup(struct vb2_buffer *vb)
> > > > +{
> > > > + struct isp4vid_dev *isp_vdev = vb2_get_drv_priv(vb->vb2_queue);
> > > > + struct isp4vid_vb2_buf *buf = vb->planes[0].mem_priv;
> > > > +
> > > > + dev_dbg(isp_vdev->dev, "%s|index=%u vb->memory %u",
> > > > + isp_vdev->vdev.name, vb->index, vb->memory);
> > > > +
> > > > + if (!buf) {
> > > > + dev_err(isp_vdev->dev, "Invalid buf handle");
> > > > + return;
> > > > + }
> > > > +
> > > > + // release implicit dmabuf reference here for vb2 buffer
> > > > + // of type MMAP and is exported
> > > > + if (vb->memory == VB2_MEMORY_MMAP && buf->is_expbuf) {
> > > > + dma_buf_put(buf->dbuf);
> > > > + dev_dbg(isp_vdev->dev,
> > > > + "put dmabuf for vb->memory %d expbuf %d",
> > > > + vb->memory,
> > > > + buf->is_expbuf);
> > > > + }
> > > > +}
> > > > +
> > >
> > > Remove the isp4vid_qops_buffer_cleanup() function. It causes a use-after-free by
> > > doing an extra dma_buf_put(). This function isn't needed now that the refcount
> > > issues are solved.
> > >
> > Will have a try
> >
> > > [snip]
> > >
> > > > +static const struct vb2_ops isp4vid_qops = {
> > > > + .queue_setup = isp4vid_qops_queue_setup,
> > > > + .buf_cleanup = isp4vid_qops_buffer_cleanup,
> > >
> > > Remove the .buf_cleanup hook too.
> > >
> > Will have a try
> >
> > > > + .buf_queue = isp4vid_qops_buffer_queue,
> > > > + .start_streaming = isp4vid_qops_start_streaming,
> > > > + .stop_streaming = isp4vid_qops_stop_streaming,
> > > > + .wait_prepare = vb2_ops_wait_prepare,
> > > > + .wait_finish = vb2_ops_wait_finish,
> > > > +};
> > >
> > > [snip]
> > >
> > > Along with the changes from my other emails, I believe this finally fixes all of
> > > the refcounting issues. No more UaF or leaks here. :-)
> > >
> > > Sultan
> > Tried changes in this and other two mails together, found the kernel will
> > crash when re-open cheese App (means open cheese, close it and then open it
> > again), the crash stack dump is shown below
> >
> > [ 38.008686] amdgpu 0000:c3:00.0: amdgpu: power on isp suc
> > [ 38.032693] amdgpu 0000:c3:00.0: amdgpu: set xclk 788 suc, reg_val 800
> > [ 38.060866] amdgpu 0000:c3:00.0: amdgpu: set iclk 788 suc, reg_val 792
> > [ 38.060877] amdgpu 0000:c3:00.0: amdgpu: set xclk 788 iclk 788 to
> > performance state 1 suc
> > [ 38.425284] amdgpu 0000:c3:00.0: amdgpu: isp set performance do none to
> > state 0
> > [ 38.448631] amdgpu 0000:c3:00.0: amdgpu: power off isp suc
> > [ 38.508368] amdgpu 0000:c3:00.0: amdgpu: power on isp suc
> > [ 38.538525] amdgpu 0000:c3:00.0: amdgpu: set xclk 788 suc, reg_val 800
> > [ 38.568839] amdgpu 0000:c3:00.0: amdgpu: set iclk 788 suc, reg_val 792
> > [ 38.568851] amdgpu 0000:c3:00.0: amdgpu: set xclk 788 iclk 788 to
> > performance state 1 suc
> > [ 38.997779] amdgpu 0000:c3:00.0: amdgpu: isp set performance do none to
> > state 0
> > [ 39.029297] amdgpu 0000:c3:00.0: amdgpu: power off isp suc
> > [ 39.084010] BUG: kernel NULL pointer dereference, address:
> > 0000000000000008
> > [ 39.084024] #PF: supervisor read access in kernel mode
> > [ 39.084028] #PF: error_code(0x0000) - not-present page
> > [ 39.084031] PGD 0 P4D 0
> > [ 39.084037] Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI
> > [ 39.084042] CPU: 3 UID: 1000 PID: 3119 Comm: viewfinderbin-q Not tainted
> > 6.14.0-rc2+ #944
> > [ 39.084046] Hardware name: HP HP ZBook Ultra G1a 14 inch Mobile
> > Workstation PC/8D01, BIOS X89 Ver. 01.03.00 04/25/2025
> > [ 39.084049] RIP: 0010:validate_page_before_insert+0x5/0xc0
> > [ 39.084060] Code: 31 c9 31 ff 45 31 c0 c3 cc cc cc cc 66 0f 1f 84 00 00
> > 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 <48>
> > 8b 46 08 a8 01 75 7a 66 90 48 89 f0 8b 50 34 85 d2 0f 84 8c 00
> > [ 39.084064] RSP: 0018:ffffb95e05e7b6a0 EFLAGS: 00010202
> > [ 39.084067] RAX: 0000000000000000 RBX: 8000000000000025 RCX:
> > 0000000000000000
> > [ 39.084069] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
> > ffff9efa10e400b8
> > [ 39.084071] RBP: ffffb95e05e7b6e0 R08: 0000000000000000 R09:
> > 0000000000000000
> > [ 39.084072] R10: 0000000000000000 R11: 0000000000000000 R12:
> > ffff9efa10e400b8
> > [ 39.084074] R13: ffffb95e0e055000 R14: 00007fa3d6119000 R15:
> > 0000000000000000
> > [ 39.084076] FS: 00007fa3f4bf96c0(0000) GS:ffff9f050d780000(0000)
> > knlGS:0000000000000000
> > [ 39.084078] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 39.084080] CR2: 0000000000000008 CR3: 0000000137bba000 CR4:
> > 0000000000750ef0
> > [ 39.084083] PKRU: 55555554
> > [ 39.084084] Call Trace:
> > [ 39.084087] <TASK>
> > [ 39.084093] ? show_regs+0x71/0x90
> > [ 39.084099] ? __die+0x25/0x80
> > [ 39.084102] ? page_fault_oops+0x15c/0x570
> > [ 39.084108] ? do_user_addr_fault+0x4a9/0x810
> > [ 39.084111] ? __mod_memcg_lruvec_state+0xde/0x280
> > [ 39.084117] ? exc_page_fault+0x83/0x1d0
> > [ 39.084123] ? asm_exc_page_fault+0x27/0x30
> > [ 39.084131] ? validate_page_before_insert+0x5/0xc0
> > [ 39.084134] ? vm_insert_page+0xd4/0x1a0
> > [ 39.084139] remap_vmalloc_range_partial+0xe3/0x160
> > [ 39.084145] remap_vmalloc_range+0x21/0x40
> > [ 39.084153] isp4vid_vb2_mmap+0x2d/0x130 [amd_capture]
> > [ 39.084164] isp4vid_vb2_dmabuf_ops_mmap+0x12/0x20 [amd_capture]
> > [ 39.084168] dma_buf_mmap_internal+0x41/0x70
> > [ 39.084173] __mmap_region+0x62f/0xbc0
> > [ 39.084179] mmap_region+0x67/0xe0
> > [ 39.084181] do_mmap+0x52b/0x650
> > [ 39.084187] vm_mmap_pgoff+0xf4/0x1c0
> > [ 39.084194] ksys_mmap_pgoff+0x182/0x250
> > [ 39.084198] __x64_sys_mmap+0x33/0x70
> > [ 39.084202] x64_sys_call+0x2541/0x26f0
> > [ 39.084206] do_syscall_64+0x70/0x130
> > [ 39.084212] ? __rseq_handle_notify_resume+0xa4/0x520
> > [ 39.084216] ? do_futex+0x17f/0x220
> > [ 39.084220] ? restore_fpregs_from_fpstate+0x3d/0xd0
> > [ 39.084225] ? switch_fpu_return+0x50/0xe0
> > [ 39.084229] ? syscall_exit_to_user_mode+0x18c/0x1c0
> > [ 39.084234] ? do_syscall_64+0x7c/0x130
> > [ 39.084237] ? __pfx_futex_wake_mark+0x10/0x10
> > [ 39.084241] ? hrtimer_cancel+0x15/0x50
> > [ 39.084246] ? futex_wait+0x7c/0x120
> > [ 39.084249] ? __pfx_hrtimer_wakeup+0x10/0x10
> > [ 39.084254] ? __rseq_handle_notify_resume+0xa4/0x520
> > [ 39.084256] ? do_futex+0x17f/0x220
> > [ 39.084258] ? restore_fpregs_from_fpstate+0x3d/0xd0
> > [ 39.084261] ? switch_fpu_return+0x50/0xe0
> > [ 39.084264] ? syscall_exit_to_user_mode+0x18c/0x1c0
> > [ 39.084268] ? do_syscall_64+0x7c/0x130
> > [ 39.084272] ? __count_memcg_events+0xcd/0x190
> > [ 39.084276] ? count_memcg_events.constprop.0+0x2a/0x50
> > [ 39.084279] ? handle_mm_fault+0x1ef/0x2d0
> > [ 39.084284] ? do_user_addr_fault+0x58d/0x810
> > [ 39.084286] ? irqentry_exit_to_user_mode+0x33/0x180
> > [ 39.084291] ? irqentry_exit+0x43/0x50
> > [ 39.084294] ? exc_page_fault+0x94/0x1d0
> > [ 39.084298] entry_SYSCALL_64_after_hwframe+0x76/0x7e
> > [ 39.084302] RIP: 0033:0x7fa463b2531c
> > [ 39.084305] Code: 1e fa 41 f7 c1 ff 0f 00 00 75 33 55 48 89 e5 41 54 41
> > 89 cc 53 48 89 fb 48 85 ff 74 41 45 89 e2 48 89 df b8 09 00 00 00 0f 05 <48>
> > 3d 00 f0 ff ff 77 7c 5b 41 5c 5d c3 0f 1f 80 00 00 00 00 48 8b
> > [ 39.084308] RSP: 002b:00007fa3f4bf79e0 EFLAGS: 00000246 ORIG_RAX:
> > 0000000000000009
> > [ 39.084311] RAX: ffffffffffffffda RBX: 0000000000000000 RCX:
> > 00007fa463b2531c
> > [ 39.084312] RDX: 0000000000000001 RSI: 00000000007782c0 RDI:
> > 0000000000000000
> > [ 39.084314] RBP: 00007fa3f4bf79f0 R08: 0000000000000047 R09:
> > 0000000000000000
> > [ 39.084315] R10: 0000000000000001 R11: 0000000000000246 R12:
> > 0000000000000001
> > [ 39.084317] R13: 0000000000000000 R14: 00007fa3f8019b48 R15:
> > 00007fa3f4bf7b60
> > [ 39.084320] </TASK>
> > [ 39.084321] Modules linked in: snd_seq_dummy snd_hrtimer hid_sensor_prox
> > hid_sensor_gyro_3d hid_sensor_trigger industrialio_triggered_buffer
> > kfifo_buf hid_sensor_iio_common industrialio hid_sensor_hub rfcomm cmac
> > algif_hash algif_skcipher af_alg hid_logitech_hidpp ov05c10 v4l2_cci
> > amd_capture v4l2_fwnode videobuf2_memops videobuf2_v4l2 videobuf2_common
> > v4l2_async videodev pinctrl_amdisp i2c_designware_amdisp qrtr bnep btusb
> > btrtl btintel btbcm btmtk bluetooth hid_logitech_dj intel_rapl_msr amd_atl
> > intel_rapl_common binfmt_misc nls_iso8859_1 snd_acp_legacy_mach snd_acp_mach
> > snd_soc_nau8821 snd_acp3x_rn amdgpu edac_mce_amd snd_ctl_led
> > snd_hda_codec_realtek snd_acp70 snd_hda_codec_generic snd_acp_i2s
> > snd_acp_pdm snd_hda_scodec_component snd_soc_dmic snd_acp_pcm
> > snd_sof_amd_rembrandt snd_sof_amd_renoir snd_sof_amd_acp snd_sof_pci
> > snd_sof_xtensa_dsp snd_hda_codec_hdmi snd_sof snd_sof_utils snd_pci_ps
> > snd_soc_acpi_amd_match snd_amd_sdw_acpi soundwire_amd
> > soundwire_generic_allocation soundwire_bus snd_hda_intel kvm_amd
> > [ 39.084385] snd_soc_sdca snd_intel_dspcfg snd_intel_sdw_acpi
> > snd_soc_core snd_hda_codec amdxcp kvm snd_compress
> > drm_panel_backlight_quirks snd_hda_core snd_usb_audio gpu_sched ac97_bus
> > polyval_clmulni snd_pcm_dmaengine polyval_generic ghash_clmulni_intel
> > drm_buddy snd_usbmidi_lib snd_seq_midi snd_rpl_pci_acp6x sha256_ssse3
> > snd_ump drm_ttm_helper snd_seq_midi_event snd_hwdep sha1_ssse3 ttm
> > aesni_intel drm_exec snd_rawmidi drm_suballoc_helper snd_acp_pci mc
> > crypto_simd snd_acp_legacy_common drm_client_lib cryptd drm_display_helper
> > snd_pci_acp6x snd_seq rapl hp_wmi cec wmi_bmof snd_pcm sparse_keymap
> > snd_seq_device rc_core snd_timer snd_pci_acp5x drm_kms_helper
> > snd_rn_pci_acp3x amd_pmf snd i2c_algo_bit snd_acp_config i2c_piix4
> > snd_soc_acpi amdtee soundcore snd_pci_acp3x i2c_smbus ccp joydev tee
> > input_leds serial_multi_instantiate amd_pmc platform_profile wireless_hotkey
> > mac_hid serio_raw sch_fq_codel msr parport_pc ppdev lp parport efi_pstore
> > nfnetlink dmi_sysfs ip_tables x_tables autofs4 r8152 mii usbhid
> > hid_multitouch
> > [ 39.084451] hid_generic nvme ucsi_acpi i2c_hid_acpi video typec_ucsi
> > i2c_hid amd_sfh thunderbolt hid nvme_core typec wmi drm
> > [ 39.084465] CR2: 0000000000000008
> > [ 39.084468] ---[ end trace 0000000000000000 ]---
> > [ 39.116114] amdgpu 0000:c3:00.0: amdgpu: power on isp suc
> > [ 39.159519] amdgpu 0000:c3:00.0: amdgpu: set xclk 788 suc, reg_val 800
> > [ 39.201325] amdgpu 0000:c3:00.0: amdgpu: set iclk 788 suc, reg_val 792
> > [ 39.201334] amdgpu 0000:c3:00.0: amdgpu: set xclk 788 iclk 788 to
> > performance state 1 suc
> > [ 39.343894] RIP: 0010:validate_page_before_insert+0x5/0xc0
> > [ 39.343907] Code: 31 c9 31 ff 45 31 c0 c3 cc cc cc cc 66 0f 1f 84 00 00
> > 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 <48>
> > 8b 46 08 a8 01 75 7a 66 90 48 89 f0 8b 50 34 85 d2 0f 84 8c 00
> > [ 39.343909] RSP: 0018:ffffb95e05e7b6a0 EFLAGS: 00010202
> > [ 39.343911] RAX: 0000000000000000 RBX: 8000000000000025 RCX:
> > 0000000000000000
> > [ 39.343913] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
> > ffff9efa10e400b8
> > [ 39.343913] RBP: ffffb95e05e7b6e0 R08: 0000000000000000 R09:
> > 0000000000000000
> > [ 39.343914] R10: 0000000000000000 R11: 0000000000000000 R12:
> > ffff9efa10e400b8
> > [ 39.343915] R13: ffffb95e0e055000 R14: 00007fa3d6119000 R15:
> > 0000000000000000
> > [ 39.343916] FS: 00007fa3f4bf96c0(0000) GS:ffff9f050d780000(0000)
> > knlGS:0000000000000000
> > [ 39.343917] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 39.343918] CR2: 0000000000000008 CR3: 0000000137bba000 CR4:
> > 0000000000750ef0
> > [ 39.343919] PKRU: 55555554
> > [ 39.343920] note: viewfinderbin-q[3119] exited with irqs disabled
> >
> > This is the patch, it should have contained all your changes
> >
> > From b0a61b6b7500635928166516d5563e6de50300bb Mon Sep 17 00:00:00 2001
> > From: Bin Du <Bin.Du@amd.com>
> > Date: Mon, 28 Jul 2025 14:18:04 +0800
> > Subject: [PATCH] add comment from community
> >
> > Change-Id: I06fff629c0dc691eaeaa9d9b81e6af27cbb6adb2
> > ---
> > drivers/media/platform/amd/isp4/isp4_video.c | 59 ++++++--------------
> > 1 file changed, 17 insertions(+), 42 deletions(-)
> >
> > diff --git a/drivers/media/platform/amd/isp4/isp4_video.c
> > b/drivers/media/platform/amd/isp4/isp4_video.c
> > index a1376498c246..b210a0b1e49b 100644
> > --- a/drivers/media/platform/amd/isp4/isp4_video.c
> > +++ b/drivers/media/platform/amd/isp4/isp4_video.c
> > @@ -183,7 +183,7 @@ static int isp4vid_vb2_mmap(void *buf_priv, struct
> > vm_area_struct *vma)
> > vm_flags_set(vma, VM_DONTEXPAND);
> >
> > dev_dbg(buf->dev, "mmap isp user bo 0x%llx size %ld refcount %d\n",
> > - buf->gpu_addr, buf->size, buf->refcount.refs.counter);
> > + buf->gpu_addr, buf->size, refcount_read(&buf->refcount));
> >
> > return 0;
> > }
> > @@ -214,14 +214,9 @@ static void isp4vid_vb2_detach_dmabuf(void *mem_priv)
> > return;
> > }
> >
> > - struct iosys_map map = IOSYS_MAP_INIT_VADDR(buf->vaddr);
> > -
> > dev_dbg(buf->dev, "detach dmabuf of isp user bo 0x%llx size %ld",
> > buf->gpu_addr, buf->size);
> >
> > - if (buf->vaddr)
> > - dma_buf_vunmap_unlocked(buf->dbuf, &map);
> > -
> > kfree(buf);
> > }
> >
> > @@ -470,21 +465,25 @@ static struct dma_buf *isp4vid_vb2_get_dmabuf(struct
> > vb2_buffer *vb,
> > unsigned long flags)
> > {
> > struct isp4vid_vb2_buf *buf = buf_priv;
> > - struct dma_buf *dbuf;
> > + struct dma_buf *dbuf = buf->dbuf;
> > +
> > + if (dbuf) {
> > + dev_dbg(buf->dev, "dbuf already created, reuse %s dbuf\n",
> > + buf->is_expbuf ? "exported" : "implicit");
> > + get_dma_buf(dbuf);
> >
> > - if (buf->dbuf) {
> > - dev_dbg(buf->dev, "dbuf already created, reuse implicit dbuf\n");
> > - dbuf = buf->dbuf;
> > } else {
> > dbuf = isp4vid_get_dmabuf(vb, buf_priv, flags);
> > + if (!dbuf)
> > + return NULL;
> > +
> > dev_dbg(buf->dev, "created new dbuf\n");
> > + buf->is_expbuf = true;
> > + refcount_inc(&buf->refcount);
> > }
> >
> > - buf->is_expbuf = true;
> > - refcount_inc(&buf->refcount);
> > -
> > dev_dbg(buf->dev, "buf exported, refcount %d\n",
> > - buf->refcount.refs.counter);
> > + refcount_read(&buf->refcount));
> >
> > return dbuf;
> > }
> > @@ -579,8 +578,9 @@ static void isp4vid_vb2_put(void *buf_priv)
> > {
> > struct isp4vid_vb2_buf *buf = (struct isp4vid_vb2_buf *)buf_priv;
> > unsigned int ref_cnt = refcount_read(&buf->refcount);
> > + struct device *dev = buf->dev;
> >
> > - dev_dbg(buf->dev,
> > + dev_dbg(dev,
> > "release isp user bo 0x%llx size %ld refcount %u is_expbuf %d\n",
> > buf->gpu_addr, buf->size,
> > ref_cnt, buf->is_expbuf);
> > @@ -598,7 +598,7 @@ static void isp4vid_vb2_put(void *buf_priv)
> > /* the ref_cnt - 1 is just a predicted value as reference, can't
> > * guarantee it's the actual value now
> > */
> > - dev_warn(buf->dev, "ignore buffer free, refcount %u > 0\n", ref_cnt - 1);
> > + dev_warn(dev, "ignore buffer free, refcount %u > 0\n", ref_cnt - 1);
> > }
> > }
> >
> > @@ -642,7 +642,7 @@ static void *isp4vid_vb2_alloc(struct vb2_buffer *vb,
> > struct device *dev,
> > refcount_set(&buf->refcount, 1);
> >
> > dev_dbg(dev, "allocated isp user bo 0x%llx size %ld refcount %d\n",
> > - buf->gpu_addr, buf->size, buf->refcount.refs.counter);
> > + buf->gpu_addr, buf->size, refcount_read(&buf->refcount));
> >
> > return buf;
> > err_free:
> > @@ -1140,30 +1140,6 @@ static void isp4vid_qops_buffer_queue(struct
> > vb2_buffer *vb)
> > mutex_unlock(&isp_vdev->buf_list_lock);
> > }
> >
> > -static void isp4vid_qops_buffer_cleanup(struct vb2_buffer *vb)
> > -{
> > - struct isp4vid_dev *isp_vdev = vb2_get_drv_priv(vb->vb2_queue);
> > - struct isp4vid_vb2_buf *buf = vb->planes[0].mem_priv;
> > -
> > - dev_dbg(isp_vdev->dev, "%s|index=%u vb->memory %u",
> > - isp_vdev->vdev.name, vb->index, vb->memory);
> > -
> > - if (!buf) {
> > - dev_err(isp_vdev->dev, "Invalid buf handle");
> > - return;
> > - }
> > -
> > - // release implicit dmabuf reference here for vb2 buffer
> > - // of type MMAP and is exported
> > - if (vb->memory == VB2_MEMORY_MMAP && buf->is_expbuf) {
> > - dma_buf_put(buf->dbuf);
> > - dev_dbg(isp_vdev->dev,
> > - "put dmabuf for vb->memory %d expbuf %d",
> > - vb->memory,
> > - buf->is_expbuf);
> > - }
> > -}
> > -
> > static int isp4vid_qops_start_streaming(struct vb2_queue *vq,
> > unsigned int count)
> > {
> > @@ -1343,7 +1319,6 @@ static int isp4vid_fill_buffer_size(struct isp4vid_dev
> > *isp_vdev)
> >
> > static const struct vb2_ops isp4vid_qops = {
> > .queue_setup = isp4vid_qops_queue_setup,
> > - .buf_cleanup = isp4vid_qops_buffer_cleanup,
> > .buf_queue = isp4vid_qops_buffer_queue,
> > .start_streaming = isp4vid_qops_start_streaming,
> > .stop_streaming = isp4vid_qops_stop_streaming,
> > --
> > 2.34.1
>
> The patch looks correct. I will get back to you on this after doing some testing
> myself.
>
> FYI, I can only test these changes with the old isp4 driver right now, since the
> new isp4 driver doesn't work for me as mentioned in my other email. So far,
> something does seem wrong after these changes I suggested because they break the
> camera on the old isp4 driver too.

Following up on this: there were several more issues hiding in the driver that
needed to be fixed unfortunately. I ended up making a lot of changes to fix all
of the buffer lifetime issues, and I created individual commits for this work
because it was getting hard to keep track of all the changes.

I think I'll have this completed tomorrow and will provide a link to my tree
with my commits. Hopefully your internal branch hasn't diverged too much from
this patchset submission, otherwise there may be some conflicts to resolve.

Sultan