Linux 7.0-rc4: v4l2src0:src: page allocation failure - increased memory usage in 7.0?

Linux 7.0-rc4: v4l2src0:src: page allocation failure - increased memory usage in 7.0?

[Marek Marczykowski-Górecki]

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Hello,

When testing 7.0-rc4 (and also got it with 7.0-rc1), I got page
allocation failure in uvcvideo when using v4l2 camera in a VM. The setup
is rather memory constrained - it's a HVM with just 300MB of memory
running on Xen, with PCI passthrough of USB controllers (to which an USB
camera is connected). But the very same setup works just fine with older
kernel (last known good is 6.19.5, built with the same config).

I'm not exactly sure if uvcvideo is really to blame here, or is it just
a victim of something else using more memory. Any advice how to check
for that?

The specific error is:

    [  739.040844] systemd-journald[251]: Under memory pressure, flushing caches.
    [  739.193589] v4l2src0:src: page allocation failure: order:5, mode:0xcc4(GFP_KERNEL|GFP_DMA32), nodemask=(null),cpuset=/,mems_allowed=0
    [  739.193645] CPU: 0 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full) 
    [  739.193648] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
    [  739.193649] Call Trace:
    [  739.193652]  <TASK>
    [  739.193656]  dump_stack_lvl+0x5d/0x80
    [  739.193661]  warn_alloc+0x162/0x190
    [  739.193665]  ? __alloc_pages_direct_compact+0x1bc/0x220
    [  739.193669]  __alloc_pages_slowpath.constprop.0+0x4ea/0xb30
    [  739.193672]  ? kernfs_activate+0x4c/0x60
    [  739.193676]  __alloc_frozen_pages_noprof+0x2ff/0x340
    [  739.193679]  __alloc_pages_noprof+0xe/0x20
    [  739.193682]  __dma_direct_alloc_pages.isra.0+0x183/0x310
    [  739.193688]  dma_direct_alloc_pages+0x3f/0x190
    [  739.193693]  dma_alloc_noncontiguous+0xdd/0x290
    [  739.193698]  ? usb_create_ep_devs+0xab/0x100
    [  739.193701]  usb_alloc_noncoherent+0x45/0xa0
    [  739.193709]  uvc_alloc_urb_buffers.part.0+0x93/0x130 [uvcvideo]
    [  739.193722]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
    [  739.193735]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
    [  739.193744]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
    [  739.193752]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
    [  739.193761]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
    [  739.193767]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
    [  739.193773]  __video_do_ioctl+0x419/0x540 [videodev]
    [  739.193799]  video_usercopy+0x23b/0x630 [videodev]
    [  739.193819]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
    [  739.193836]  v4l2_ioctl+0x6b/0xa0 [videodev]
    [  739.193851]  __x64_sys_ioctl+0x96/0xe0
    [  739.193855]  do_syscall_64+0x120/0x6c0
    [  739.193859]  ? do_read_fault+0xf5/0x220
    [  739.193863]  ? do_fault+0x148/0x270
    [  739.193865]  ? __handle_mm_fault+0x470/0x6c0
    [  739.193868]  ? count_memcg_events+0xeb/0x1b0
    [  739.193871]  ? handle_mm_fault+0x220/0x340
    [  739.193873]  ? do_user_addr_fault+0x1e5/0x7f0
    [  739.193876]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
    [  739.193880]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
    [  739.193883] RIP: 0033:0x738e787000ed
    [  739.193886] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
    [  739.193888] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
    [  739.193890] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX: 0000738e787000ed
    [  739.193892] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI: 0000000000000010
    [  739.193893] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09: 0000000000000000
    [  739.193894] R10: 0000738e6400ae30 R11: 0000000000000246 R12: 0000000000000000
    [  739.193895] R13: 0000738e640012d0 R14: 0000738e64008850 R15: 0000000000000002
    [  739.193897]  </TASK>
    [  739.193907] Mem-Info:
    [  739.194897] active_anon:362 inactive_anon:3172 isolated_anon:0
    [  739.194897]  active_file:2498 inactive_file:11687 isolated_file:1
    [  739.194897]  unevictable:0 dirty:0 writeback:4
    [  739.194897]  slab_reclaimable:3707 slab_unreclaimable:10022
    [  739.194897]  mapped:4710 shmem:9 pagetables:1021
    [  739.194897]  sec_pagetables:0 bounce:0
    [  739.194897]  kernel_misc_reclaimable:0
    [  739.194897]  free:3452 free_pcp:1 free_cma:0
    [  739.195008] Node 0 active_anon:1448kB inactive_anon:12688kB active_file:9992kB inactive_file:46748kB unevictable:0kB isolated(anon):0kB isolated(file):4kB mapped:18840kB dirty:0kB writeback:16kB shmem:36kB shmem_thp:0kB shmem_pmdmapped:0kB anon_thp:0kB kernel_stack:2416kB pagetables:4084kB sec_pagetables:0kB all_unreclaimable? no Balloon:16384kB
    [  739.195097] Node 0 DMA free:2828kB boost:0kB min:132kB low:164kB high:196kB reserved_highatomic:0KB free_highatomic:0KB active_anon:224kB inactive_anon:940kB active_file:1360kB inactive_file:2408kB unevictable:0kB writepending:0kB zspages:0kB present:15992kB managed:15360kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
    [  739.195186] lowmem_reserve[]: 0 195 195 195 195
    [  739.196280] Node 0 DMA32 free:14880kB boost:3856kB min:5572kB low:6000kB high:6428kB reserved_highatomic:0KB free_highatomic:0KB active_anon:1224kB inactive_anon:11728kB active_file:8632kB inactive_file:40024kB unevictable:0kB writepending:16kB zspages:0kB present:274348kB managed:200080kB mlocked:0kB bounce:0kB free_pcp:316kB local_pcp:236kB free_cma:0kB
    [  739.196372] lowmem_reserve[]: 0 0 0 0 0
    [  739.196388] Node 0 DMA: 193*4kB (UM) 213*8kB (UM) 22*16kB (UM) 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 2828kB
    [  739.196433] Node 0 DMA32: 1631*4kB (UME) 764*8kB (UME) 138*16kB (UME) 8*32kB (UM) 3*64kB (M) 1*128kB (M) 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 15420kB
    [  739.196487] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
    [  739.196514] 14914 total pagecache pages
    [  739.196527] 2073 pages in swap cache
    [  739.196539] Free swap  = 961672kB
    [  739.196551] Total swap = 1048572kB
    [  739.196563] 72585 pages RAM
    [  739.196572] 0 pages HighMem/MovableOnly
    [  739.196584] 18725 pages reserved
    [  739.196596] 0 pages cma reserved
    [  739.196608] 0 pages hwpoisoned
    [  739.196620] Memory cgroup min protection 0kB -- low protection 0kB
    [  739.196627] ------------[ cut here ]------------

Additionally, this failure isn't handled gracefully, it's followed with:

    [  739.196672] UBSAN: shift-out-of-bounds in /builddir/build/BUILD/kernel-latest-7.0-build/kernel-latest-7.0/linux-7.0-rc4/mm/page_alloc.c:1403:22
    [  739.196710] shift exponent 52 is too large for 32-bit type 'int'
    [  739.196730] CPU: 1 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full) 
    [  739.196733] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
    [  739.196734] Call Trace:
    [  739.196737]  <TASK>
    [  739.196739]  dump_stack_lvl+0x5d/0x80
    [  739.196744]  ubsan_epilogue+0x5/0x2b
    [  739.196746]  __ubsan_handle_shift_out_of_bounds.cold+0x61/0xe6
    [  739.196749]  __free_pages_ok.cold+0x13/0xa8
    [  739.196753]  dma_free_noncontiguous+0xbf/0xe0
    [  739.196756]  ? usb_free_noncoherent+0x3a/0x60
    [  739.196761]  uvc_free_urb_buffers+0x38/0x90 [uvcvideo]
    [  739.196773]  uvc_alloc_urb_buffers.part.0+0xe6/0x130 [uvcvideo]
    [  739.196781]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
    [  739.196789]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
    [  739.196797]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
    [  739.196806]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
    [  739.196813]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
    [  739.196819]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
    [  739.196824]  __video_do_ioctl+0x419/0x540 [videodev]
    [  739.196847]  video_usercopy+0x23b/0x630 [videodev]
    [  739.196863]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
    [  739.196880]  v4l2_ioctl+0x6b/0xa0 [videodev]
    [  739.196895]  __x64_sys_ioctl+0x96/0xe0
    [  739.196898]  do_syscall_64+0x120/0x6c0
    [  739.196902]  ? do_read_fault+0xf5/0x220
    [  739.196906]  ? do_fault+0x148/0x270
    [  739.196908]  ? __handle_mm_fault+0x470/0x6c0
    [  739.196911]  ? count_memcg_events+0xeb/0x1b0
    [  739.196914]  ? handle_mm_fault+0x220/0x340
    [  739.196916]  ? do_user_addr_fault+0x1e5/0x7f0
    [  739.196920]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
    [  739.196924]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
    [  739.196926] RIP: 0033:0x738e787000ed
    [  739.196929] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
    [  739.196930] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
    [  739.196933] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX: 0000738e787000ed
    [  739.196934] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI: 0000000000000010
    [  739.196935] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09: 0000000000000000
    [  739.196936] R10: 0000738e6400ae30 R11: 0000000000000246 R12: 0000000000000000
    [  739.196937] R13: 0000738e640012d0 R14: 0000738e64008850 R15: 0000000000000002
    [  739.196939]  </TASK>
    [  739.196940] ---[ end trace ]---
    [  739.197835] BUG: Bad page state in process v4l2src0:src  pfn:009a0
    [  739.198028] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x2a pfn:0x9a0
    [  739.198054] flags: 0x7ffffc0000000(node=0|zone=0|lastcpupid=0x1fffff)
    [  739.198074] page_type: f0(buddy)
    [  739.198088] raw: 0007ffffc0000000 fffffac1c0026a08 fffffac1c0025e08 0000000000000000
    [  739.198111] raw: 000000000000002a 0000000000000002 00000000f0000000 0000000000000000
    [  739.198133] page dumped because: nonzero mapcount
    [  739.198149] Modules linked in: nft_reject_ipv6 nf_reject_ipv6 nft_reject_ipv4 nf_reject_ipv4 nft_reject nft_ct nft_masq nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables uvcvideo ath3k btusb btmtk uvc videobuf2_vmalloc btrtl videobuf2_memops videobuf2_v4l2 cdc_mbim btbcm cdc_ncm videobuf2_common btintel cdc_ether usbnet videodev bluetooth mii cdc_wdm mc rfkill cdc_acm joydev intel_rapl_msr intel_rapl_common ghash_clmulni_intel xhci_pci xhci_hcd ehci_pci ehci_hcd pcspkr i2c_piix4 ata_generic pata_acpi i2c_smbus serio_raw xen_scsiback target_core_mod xen_netback xen_privcmd xen_gntdev xen_gntalloc xen_blkback xen_evtchn i2c_dev fuse loop nfnetlink overlay xen_blkfront
    [  739.198472] CPU: 1 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full) 
    [  739.198475] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
    [  739.198477] Call Trace:
    [  739.198479]  <TASK>
    [  739.198480]  dump_stack_lvl+0x5d/0x80
    [  739.198485]  bad_page.cold+0x7a/0x91
    [  739.198488]  __free_pages_ok+0x481/0x680
    [  739.198491]  dma_free_noncontiguous+0xbf/0xe0
    [  739.198494]  ? usb_free_noncoherent+0x3a/0x60
    [  739.198497]  uvc_free_urb_buffers+0x38/0x90 [uvcvideo]
    [  739.198507]  uvc_alloc_urb_buffers.part.0+0xe6/0x130 [uvcvideo]
    [  739.198515]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
    [  739.198523]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
    [  739.198531]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
    [  739.198539]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
    [  739.198546]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
    [  739.198551]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
    [  739.198555]  __video_do_ioctl+0x419/0x540 [videodev]
    [  739.198574]  video_usercopy+0x23b/0x630 [videodev]
    [  739.198590]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
    [  739.198607]  v4l2_ioctl+0x6b/0xa0 [videodev]
    [  739.198622]  __x64_sys_ioctl+0x96/0xe0
    [  739.198625]  do_syscall_64+0x120/0x6c0
    [  739.198629]  ? do_read_fault+0xf5/0x220
    [  739.198632]  ? do_fault+0x148/0x270
    [  739.198635]  ? __handle_mm_fault+0x470/0x6c0
    [  739.198637]  ? count_memcg_events+0xeb/0x1b0
    [  739.198640]  ? handle_mm_fault+0x220/0x340
    [  739.198642]  ? do_user_addr_fault+0x1e5/0x7f0
    [  739.198645]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
    [  739.198648]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
    [  739.198651] RIP: 0033:0x738e787000ed
    [  739.198653] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
    [  739.198654] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
    [  739.198656] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX: 0000738e787000ed
    [  739.198657] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI: 0000000000000010
    [  739.198658] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09: 0000000000000000
    [  739.198659] R10: 0000738e6400ae30 R11: 0000000000000246 R12: 0000000000000000
    [  739.198660] R13: 0000738e640012d0 R14: 0000738e64008850 R15: 0000000000000002
    [  739.198662]  </TASK>
    [  739.198663] Disabling lock debugging due to kernel taint

And eventually kernel panic:

    [  740.464422] BUG: unable to handle page fault for address: fffffac1c0800000
    [  740.464454] #PF: supervisor read access in kernel mode
    [  740.464471] #PF: error_code(0x0000) - not-present page
    [  740.464488] PGD 11be0067 P4D 11be0067 PUD 1148f067 PMD 0 

Full console log is at: https://gist.github.com/marmarek/5d839f419b1d56e71a48e74ae66f0e7a

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

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Re: Linux 7.0-rc4: v4l2src0:src: page allocation failure - increased memory usage in 7.0?

[Ricardo Ribalda]

Hi Marek

Thanks a lot for the detailed report.

On Thu, 19 Mar 2026 at 01:18, Marek Marczykowski-Górecki
<marmarek@invisiblethingslab.com> wrote:
>
> Hello,
>
> When testing 7.0-rc4 (and also got it with 7.0-rc1), I got page
> allocation failure in uvcvideo when using v4l2 camera in a VM. The setup
> is rather memory constrained - it's a HVM with just 300MB of memory
> running on Xen, with PCI passthrough of USB controllers (to which an USB
> camera is connected). But the very same setup works just fine with older
> kernel (last known good is 6.19.5, built with the same config).
>
> I'm not exactly sure if uvcvideo is really to blame here, or is it just
> a victim of something else using more memory. Any advice how to check
> for that?

I have looked at at:
git diff v6.19..linus/master drivers/media/usb/uvc/

And I have not found anything that indicate me that we allocate more
memory or we allocate it differently.

>
> The specific error is:
>
>     [  739.040844] systemd-journald[251]: Under memory pressure, flushing caches.
>     [  739.193589] v4l2src0:src: page allocation failure: order:5, mode:0xcc4(GFP_KERNEL|GFP_DMA32), nodemask=(null),cpuset=/,mems_allowed=0
>     [  739.193645] CPU: 0 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full)
>     [  739.193648] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
>     [  739.193649] Call Trace:
>     [  739.193652]  <TASK>
>     [  739.193656]  dump_stack_lvl+0x5d/0x80
>     [  739.193661]  warn_alloc+0x162/0x190
>     [  739.193665]  ? __alloc_pages_direct_compact+0x1bc/0x220
>     [  739.193669]  __alloc_pages_slowpath.constprop.0+0x4ea/0xb30
>     [  739.193672]  ? kernfs_activate+0x4c/0x60
>     [  739.193676]  __alloc_frozen_pages_noprof+0x2ff/0x340
>     [  739.193679]  __alloc_pages_noprof+0xe/0x20
>     [  739.193682]  __dma_direct_alloc_pages.isra.0+0x183/0x310
>     [  739.193688]  dma_direct_alloc_pages+0x3f/0x190
>     [  739.193693]  dma_alloc_noncontiguous+0xdd/0x290
>     [  739.193698]  ? usb_create_ep_devs+0xab/0x100
>     [  739.193701]  usb_alloc_noncoherent+0x45/0xa0
>     [  739.193709]  uvc_alloc_urb_buffers.part.0+0x93/0x130 [uvcvideo]
>     [  739.193722]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
>     [  739.193735]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
>     [  739.193744]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
>     [  739.193752]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
>     [  739.193761]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
>     [  739.193767]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
>     [  739.193773]  __video_do_ioctl+0x419/0x540 [videodev]
>     [  739.193799]  video_usercopy+0x23b/0x630 [videodev]
>     [  739.193819]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
>     [  739.193836]  v4l2_ioctl+0x6b/0xa0 [videodev]
>     [  739.193851]  __x64_sys_ioctl+0x96/0xe0
>     [  739.193855]  do_syscall_64+0x120/0x6c0
>     [  739.193859]  ? do_read_fault+0xf5/0x220
>     [  739.193863]  ? do_fault+0x148/0x270
>     [  739.193865]  ? __handle_mm_fault+0x470/0x6c0
>     [  739.193868]  ? count_memcg_events+0xeb/0x1b0
>     [  739.193871]  ? handle_mm_fault+0x220/0x340
>     [  739.193873]  ? do_user_addr_fault+0x1e5/0x7f0
>     [  739.193876]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
>     [  739.193880]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
>     [  739.193883] RIP: 0033:0x738e787000ed
>     [  739.193886] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
>     [  739.193888] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
>     [  739.193890] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX: 0000738e787000ed
>     [  739.193892] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI: 0000000000000010
>     [  739.193893] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09: 0000000000000000
>     [  739.193894] R10: 0000738e6400ae30 R11: 0000000000000246 R12: 0000000000000000
>     [  739.193895] R13: 0000738e640012d0 R14: 0000738e64008850 R15: 0000000000000002
>     [  739.193897]  </TASK>
>     [  739.193907] Mem-Info:
>     [  739.194897] active_anon:362 inactive_anon:3172 isolated_anon:0
>     [  739.194897]  active_file:2498 inactive_file:11687 isolated_file:1
>     [  739.194897]  unevictable:0 dirty:0 writeback:4
>     [  739.194897]  slab_reclaimable:3707 slab_unreclaimable:10022
>     [  739.194897]  mapped:4710 shmem:9 pagetables:1021
>     [  739.194897]  sec_pagetables:0 bounce:0
>     [  739.194897]  kernel_misc_reclaimable:0
>     [  739.194897]  free:3452 free_pcp:1 free_cma:0
>     [  739.195008] Node 0 active_anon:1448kB inactive_anon:12688kB active_file:9992kB inactive_file:46748kB unevictable:0kB isolated(anon):0kB isolated(file):4kB mapped:18840kB dirty:0kB writeback:16kB shmem:36kB shmem_thp:0kB shmem_pmdmapped:0kB anon_thp:0kB kernel_stack:2416kB pagetables:4084kB sec_pagetables:0kB all_unreclaimable? no Balloon:16384kB
>     [  739.195097] Node 0 DMA free:2828kB boost:0kB min:132kB low:164kB high:196kB reserved_highatomic:0KB free_highatomic:0KB active_anon:224kB inactive_anon:940kB active_file:1360kB inactive_file:2408kB unevictable:0kB writepending:0kB zspages:0kB present:15992kB managed:15360kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>     [  739.195186] lowmem_reserve[]: 0 195 195 195 195
>     [  739.196280] Node 0 DMA32 free:14880kB boost:3856kB min:5572kB low:6000kB high:6428kB reserved_highatomic:0KB free_highatomic:0KB active_anon:1224kB inactive_anon:11728kB active_file:8632kB inactive_file:40024kB unevictable:0kB writepending:16kB zspages:0kB present:274348kB managed:200080kB mlocked:0kB bounce:0kB free_pcp:316kB local_pcp:236kB free_cma:0kB
>     [  739.196372] lowmem_reserve[]: 0 0 0 0 0
>     [  739.196388] Node 0 DMA: 193*4kB (UM) 213*8kB (UM) 22*16kB (UM) 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 2828kB
>     [  739.196433] Node 0 DMA32: 1631*4kB (UME) 764*8kB (UME) 138*16kB (UME) 8*32kB (UM) 3*64kB (M) 1*128kB (M) 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 15420kB
>     [  739.196487] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
>     [  739.196514] 14914 total pagecache pages
>     [  739.196527] 2073 pages in swap cache
>     [  739.196539] Free swap  = 961672kB
>     [  739.196551] Total swap = 1048572kB
>     [  739.196563] 72585 pages RAM
>     [  739.196572] 0 pages HighMem/MovableOnly
>     [  739.196584] 18725 pages reserved
>     [  739.196596] 0 pages cma reserved
>     [  739.196608] 0 pages hwpoisoned
>     [  739.196620] Memory cgroup min protection 0kB -- low protection 0kB
>     [  739.196627] ------------[ cut here ]------------
>
> Additionally, this failure isn't handled gracefully, it's followed with:

That should not happen.... Could you check if this fixes it:

diff --git a/drivers/media/usb/uvc/uvc_video.c
b/drivers/media/usb/uvc/uvc_video.c
index 40c76c051da2..f6c8e3223796 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -1751,7 +1751,8 @@ static void uvc_video_complete(struct urb *urb)
 /*
  * Free transfer buffers.
  */
-static void uvc_free_urb_buffers(struct uvc_streaming *stream)
+static void uvc_free_urb_buffers(struct uvc_streaming *stream,
+                                unsigned int size)
 {
        struct usb_device *udev = stream->dev->udev;
        struct uvc_urb *uvc_urb;
@@ -1760,7 +1761,7 @@ static void uvc_free_urb_buffers(struct
uvc_streaming *stream)
                if (!uvc_urb->buffer)
                        continue;

-               usb_free_noncoherent(udev, stream->urb_size, uvc_urb->buffer,
+               usb_free_noncoherent(udev, size, uvc_urb->buffer,
                                     uvc_stream_dir(stream), uvc_urb->sgt);
                uvc_urb->buffer = NULL;
                uvc_urb->sgt = NULL;
@@ -1820,7 +1821,7 @@ static int uvc_alloc_urb_buffers(struct
uvc_streaming *stream,

                        if (!uvc_alloc_urb_buffer(stream, uvc_urb, urb_size,
                                                  gfp_flags)) {
-                               uvc_free_urb_buffers(stream);
+                               uvc_free_urb_buffers(stream, urb_size);
                                break;
                        }

@@ -1868,7 +1869,7 @@ static void uvc_video_stop_transfer(struct
uvc_streaming *stream,
        }

        if (free_buffers)
-               uvc_free_urb_buffers(stream);
+               uvc_free_urb_buffers(stream, stream->urb_size);
 }

 /*
>
>     [  739.196672] UBSAN: shift-out-of-bounds in /builddir/build/BUILD/kernel-latest-7.0-build/kernel-latest-7.0/linux-7.0-rc4/mm/page_alloc.c:1403:22
>     [  739.196710] shift exponent 52 is too large for 32-bit type 'int'
>     [  739.196730] CPU: 1 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full)
>     [  739.196733] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
>     [  739.196734] Call Trace:
>     [  739.196737]  <TASK>
>     [  739.196739]  dump_stack_lvl+0x5d/0x80
>     [  739.196744]  ubsan_epilogue+0x5/0x2b
>     [  739.196746]  __ubsan_handle_shift_out_of_bounds.cold+0x61/0xe6
>     [  739.196749]  __free_pages_ok.cold+0x13/0xa8
>     [  739.196753]  dma_free_noncontiguous+0xbf/0xe0
>     [  739.196756]  ? usb_free_noncoherent+0x3a/0x60
>     [  739.196761]  uvc_free_urb_buffers+0x38/0x90 [uvcvideo]
>     [  739.196773]  uvc_alloc_urb_buffers.part.0+0xe6/0x130 [uvcvideo]
>     [  739.196781]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
>     [  739.196789]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
>     [  739.196797]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
>     [  739.196806]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
>     [  739.196813]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
>     [  739.196819]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
>     [  739.196824]  __video_do_ioctl+0x419/0x540 [videodev]
>     [  739.196847]  video_usercopy+0x23b/0x630 [videodev]
>     [  739.196863]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
>     [  739.196880]  v4l2_ioctl+0x6b/0xa0 [videodev]
>     [  739.196895]  __x64_sys_ioctl+0x96/0xe0
>     [  739.196898]  do_syscall_64+0x120/0x6c0
>     [  739.196902]  ? do_read_fault+0xf5/0x220
>     [  739.196906]  ? do_fault+0x148/0x270
>     [  739.196908]  ? __handle_mm_fault+0x470/0x6c0
>     [  739.196911]  ? count_memcg_events+0xeb/0x1b0
>     [  739.196914]  ? handle_mm_fault+0x220/0x340
>     [  739.196916]  ? do_user_addr_fault+0x1e5/0x7f0
>     [  739.196920]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
>     [  739.196924]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
>     [  739.196926] RIP: 0033:0x738e787000ed
>     [  739.196929] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
>     [  739.196930] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
>     [  739.196933] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX: 0000738e787000ed
>     [  739.196934] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI: 0000000000000010
>     [  739.196935] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09: 0000000000000000
>     [  739.196936] R10: 0000738e6400ae30 R11: 0000000000000246 R12: 0000000000000000
>     [  739.196937] R13: 0000738e640012d0 R14: 0000738e64008850 R15: 0000000000000002
>     [  739.196939]  </TASK>
>     [  739.196940] ---[ end trace ]---
>     [  739.197835] BUG: Bad page state in process v4l2src0:src  pfn:009a0
>     [  739.198028] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x2a pfn:0x9a0
>     [  739.198054] flags: 0x7ffffc0000000(node=0|zone=0|lastcpupid=0x1fffff)
>     [  739.198074] page_type: f0(buddy)
>     [  739.198088] raw: 0007ffffc0000000 fffffac1c0026a08 fffffac1c0025e08 0000000000000000
>     [  739.198111] raw: 000000000000002a 0000000000000002 00000000f0000000 0000000000000000
>     [  739.198133] page dumped because: nonzero mapcount
>     [  739.198149] Modules linked in: nft_reject_ipv6 nf_reject_ipv6 nft_reject_ipv4 nf_reject_ipv4 nft_reject nft_ct nft_masq nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables uvcvideo ath3k btusb btmtk uvc videobuf2_vmalloc btrtl videobuf2_memops videobuf2_v4l2 cdc_mbim btbcm cdc_ncm videobuf2_common btintel cdc_ether usbnet videodev bluetooth mii cdc_wdm mc rfkill cdc_acm joydev intel_rapl_msr intel_rapl_common ghash_clmulni_intel xhci_pci xhci_hcd ehci_pci ehci_hcd pcspkr i2c_piix4 ata_generic pata_acpi i2c_smbus serio_raw xen_scsiback target_core_mod xen_netback xen_privcmd xen_gntdev xen_gntalloc xen_blkback xen_evtchn i2c_dev fuse loop nfnetlink overlay xen_blkfront
>     [  739.198472] CPU: 1 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full)
>     [  739.198475] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
>     [  739.198477] Call Trace:
>     [  739.198479]  <TASK>
>     [  739.198480]  dump_stack_lvl+0x5d/0x80
>     [  739.198485]  bad_page.cold+0x7a/0x91
>     [  739.198488]  __free_pages_ok+0x481/0x680
>     [  739.198491]  dma_free_noncontiguous+0xbf/0xe0
>     [  739.198494]  ? usb_free_noncoherent+0x3a/0x60
>     [  739.198497]  uvc_free_urb_buffers+0x38/0x90 [uvcvideo]
>     [  739.198507]  uvc_alloc_urb_buffers.part.0+0xe6/0x130 [uvcvideo]
>     [  739.198515]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
>     [  739.198523]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
>     [  739.198531]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
>     [  739.198539]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
>     [  739.198546]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
>     [  739.198551]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
>     [  739.198555]  __video_do_ioctl+0x419/0x540 [videodev]
>     [  739.198574]  video_usercopy+0x23b/0x630 [videodev]
>     [  739.198590]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
>     [  739.198607]  v4l2_ioctl+0x6b/0xa0 [videodev]
>     [  739.198622]  __x64_sys_ioctl+0x96/0xe0
>     [  739.198625]  do_syscall_64+0x120/0x6c0
>     [  739.198629]  ? do_read_fault+0xf5/0x220
>     [  739.198632]  ? do_fault+0x148/0x270
>     [  739.198635]  ? __handle_mm_fault+0x470/0x6c0
>     [  739.198637]  ? count_memcg_events+0xeb/0x1b0
>     [  739.198640]  ? handle_mm_fault+0x220/0x340
>     [  739.198642]  ? do_user_addr_fault+0x1e5/0x7f0
>     [  739.198645]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
>     [  739.198648]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
>     [  739.198651] RIP: 0033:0x738e787000ed
>     [  739.198653] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
>     [  739.198654] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
>     [  739.198656] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX: 0000738e787000ed
>     [  739.198657] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI: 0000000000000010
>     [  739.198658] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09: 0000000000000000
>     [  739.198659] R10: 0000738e6400ae30 R11: 0000000000000246 R12: 0000000000000000
>     [  739.198660] R13: 0000738e640012d0 R14: 0000738e64008850 R15: 0000000000000002
>     [  739.198662]  </TASK>
>     [  739.198663] Disabling lock debugging due to kernel taint
>
> And eventually kernel panic:
>
>     [  740.464422] BUG: unable to handle page fault for address: fffffac1c0800000
>     [  740.464454] #PF: supervisor read access in kernel mode
>     [  740.464471] #PF: error_code(0x0000) - not-present page
>     [  740.464488] PGD 11be0067 P4D 11be0067 PUD 1148f067 PMD 0
>
> Full console log is at: https://gist.github.com/marmarek/5d839f419b1d56e71a48e74ae66f0e7a
>
> --
> Best Regards,
> Marek Marczykowski-Górecki
> Invisible Things Lab

Thanks!

-- 
Ricardo Ribalda

Re: Linux 7.0-rc4: v4l2src0:src: page allocation failure - increased memory usage in 7.0?

[Marek Marczykowski-Górecki]

[-- Attachment #1: Type: text/plain, Size: 451 bytes --]

On Thu, Mar 19, 2026 at 11:19:38AM +0100, Ricardo Ribalda wrote:
> On Thu, 19 Mar 2026 at 01:18, Marek Marczykowski-Górecki
> > Additionally, this failure isn't handled gracefully, it's followed with:
> 
> That should not happen.... Could you check if this fixes it:

Yes, while the page allocation failure still happens, it doesn't result
in follow up errors anymore.

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: Linux 7.0-rc4: v4l2src0:src: page allocation failure - increased memory usage in 7.0?

[Laurent Pinchart]

Hi Ricardo,

On Thu, Mar 19, 2026 at 11:19:38AM +0100, Ricardo Ribalda wrote:
> On Thu, 19 Mar 2026 at 01:18, Marek Marczykowski-Górecki wrote:
> > Hello,
> >
> > When testing 7.0-rc4 (and also got it with 7.0-rc1), I got page
> > allocation failure in uvcvideo when using v4l2 camera in a VM. The setup
> > is rather memory constrained - it's a HVM with just 300MB of memory
> > running on Xen, with PCI passthrough of USB controllers (to which an USB
> > camera is connected). But the very same setup works just fine with older
> > kernel (last known good is 6.19.5, built with the same config).
> >
> > I'm not exactly sure if uvcvideo is really to blame here, or is it just
> > a victim of something else using more memory. Any advice how to check
> > for that?
> 
> I have looked at at:
> git diff v6.19..linus/master drivers/media/usb/uvc/
> 
> And I have not found anything that indicate me that we allocate more
> memory or we allocate it differently.
> 
> > The specific error is:
> >
> >     [  739.040844] systemd-journald[251]: Under memory pressure, flushing caches.
> >     [  739.193589] v4l2src0:src: page allocation failure: order:5, mode:0xcc4(GFP_KERNEL|GFP_DMA32), nodemask=(null),cpuset=/,mems_allowed=0
> >     [  739.193645] CPU: 0 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full)
> >     [  739.193648] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
> >     [  739.193649] Call Trace:
> >     [  739.193652]  <TASK>
> >     [  739.193656]  dump_stack_lvl+0x5d/0x80
> >     [  739.193661]  warn_alloc+0x162/0x190
> >     [  739.193665]  ? __alloc_pages_direct_compact+0x1bc/0x220
> >     [  739.193669]  __alloc_pages_slowpath.constprop.0+0x4ea/0xb30
> >     [  739.193672]  ? kernfs_activate+0x4c/0x60
> >     [  739.193676]  __alloc_frozen_pages_noprof+0x2ff/0x340
> >     [  739.193679]  __alloc_pages_noprof+0xe/0x20
> >     [  739.193682]  __dma_direct_alloc_pages.isra.0+0x183/0x310
> >     [  739.193688]  dma_direct_alloc_pages+0x3f/0x190
> >     [  739.193693]  dma_alloc_noncontiguous+0xdd/0x290
> >     [  739.193698]  ? usb_create_ep_devs+0xab/0x100
> >     [  739.193701]  usb_alloc_noncoherent+0x45/0xa0
> >     [  739.193709]  uvc_alloc_urb_buffers.part.0+0x93/0x130 [uvcvideo]
> >     [  739.193722]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
> >     [  739.193735]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
> >     [  739.193744]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
> >     [  739.193752]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
> >     [  739.193761]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
> >     [  739.193767]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
> >     [  739.193773]  __video_do_ioctl+0x419/0x540 [videodev]
> >     [  739.193799]  video_usercopy+0x23b/0x630 [videodev]
> >     [  739.193819]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
> >     [  739.193836]  v4l2_ioctl+0x6b/0xa0 [videodev]
> >     [  739.193851]  __x64_sys_ioctl+0x96/0xe0
> >     [  739.193855]  do_syscall_64+0x120/0x6c0
> >     [  739.193859]  ? do_read_fault+0xf5/0x220
> >     [  739.193863]  ? do_fault+0x148/0x270
> >     [  739.193865]  ? __handle_mm_fault+0x470/0x6c0
> >     [  739.193868]  ? count_memcg_events+0xeb/0x1b0
> >     [  739.193871]  ? handle_mm_fault+0x220/0x340
> >     [  739.193873]  ? do_user_addr_fault+0x1e5/0x7f0
> >     [  739.193876]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
> >     [  739.193880]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> >     [  739.193883] RIP: 0033:0x738e787000ed
> >     [  739.193886] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
> >     [  739.193888] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> >     [  739.193890] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX: 0000738e787000ed
> >     [  739.193892] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI: 0000000000000010
> >     [  739.193893] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09: 0000000000000000
> >     [  739.193894] R10: 0000738e6400ae30 R11: 0000000000000246 R12: 0000000000000000
> >     [  739.193895] R13: 0000738e640012d0 R14: 0000738e64008850 R15: 0000000000000002
> >     [  739.193897]  </TASK>
> >     [  739.193907] Mem-Info:
> >     [  739.194897] active_anon:362 inactive_anon:3172 isolated_anon:0
> >     [  739.194897]  active_file:2498 inactive_file:11687 isolated_file:1
> >     [  739.194897]  unevictable:0 dirty:0 writeback:4
> >     [  739.194897]  slab_reclaimable:3707 slab_unreclaimable:10022
> >     [  739.194897]  mapped:4710 shmem:9 pagetables:1021
> >     [  739.194897]  sec_pagetables:0 bounce:0
> >     [  739.194897]  kernel_misc_reclaimable:0
> >     [  739.194897]  free:3452 free_pcp:1 free_cma:0
> >     [  739.195008] Node 0 active_anon:1448kB inactive_anon:12688kB active_file:9992kB inactive_file:46748kB unevictable:0kB isolated(anon):0kB isolated(file):4kB mapped:18840kB dirty:0kB writeback:16kB shmem:36kB shmem_thp:0kB shmem_pmdmapped:0kB anon_thp:0kB kernel_stack:2416kB pagetables:4084kB sec_pagetables:0kB all_unreclaimable? no Balloon:16384kB
> >     [  739.195097] Node 0 DMA free:2828kB boost:0kB min:132kB low:164kB high:196kB reserved_highatomic:0KB free_highatomic:0KB active_anon:224kB inactive_anon:940kB active_file:1360kB inactive_file:2408kB unevictable:0kB writepending:0kB zspages:0kB present:15992kB managed:15360kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> >     [  739.195186] lowmem_reserve[]: 0 195 195 195 195
> >     [  739.196280] Node 0 DMA32 free:14880kB boost:3856kB min:5572kB low:6000kB high:6428kB reserved_highatomic:0KB free_highatomic:0KB active_anon:1224kB inactive_anon:11728kB active_file:8632kB inactive_file:40024kB unevictable:0kB writepending:16kB zspages:0kB present:274348kB managed:200080kB mlocked:0kB bounce:0kB free_pcp:316kB local_pcp:236kB free_cma:0kB
> >     [  739.196372] lowmem_reserve[]: 0 0 0 0 0
> >     [  739.196388] Node 0 DMA: 193*4kB (UM) 213*8kB (UM) 22*16kB (UM) 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 2828kB
> >     [  739.196433] Node 0 DMA32: 1631*4kB (UME) 764*8kB (UME) 138*16kB (UME) 8*32kB (UM) 3*64kB (M) 1*128kB (M) 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 15420kB
> >     [  739.196487] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
> >     [  739.196514] 14914 total pagecache pages
> >     [  739.196527] 2073 pages in swap cache
> >     [  739.196539] Free swap  = 961672kB
> >     [  739.196551] Total swap = 1048572kB
> >     [  739.196563] 72585 pages RAM
> >     [  739.196572] 0 pages HighMem/MovableOnly
> >     [  739.196584] 18725 pages reserved
> >     [  739.196596] 0 pages cma reserved
> >     [  739.196608] 0 pages hwpoisoned
> >     [  739.196620] Memory cgroup min protection 0kB -- low protection 0kB
> >     [  739.196627] ------------[ cut here ]------------
> >
> > Additionally, this failure isn't handled gracefully, it's followed with:
> 
> That should not happen.... Could you check if this fixes it:
> 
> diff --git a/drivers/media/usb/uvc/uvc_video.c
> b/drivers/media/usb/uvc/uvc_video.c
> index 40c76c051da2..f6c8e3223796 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -1751,7 +1751,8 @@ static void uvc_video_complete(struct urb *urb)
>  /*
>   * Free transfer buffers.
>   */
> -static void uvc_free_urb_buffers(struct uvc_streaming *stream)
> +static void uvc_free_urb_buffers(struct uvc_streaming *stream,
> +                                unsigned int size)
>  {
>         struct usb_device *udev = stream->dev->udev;
>         struct uvc_urb *uvc_urb;
> @@ -1760,7 +1761,7 @@ static void uvc_free_urb_buffers(struct
> uvc_streaming *stream)
>                 if (!uvc_urb->buffer)
>                         continue;
> 
> -               usb_free_noncoherent(udev, stream->urb_size, uvc_urb->buffer,
> +               usb_free_noncoherent(udev, size, uvc_urb->buffer,
>                                      uvc_stream_dir(stream), uvc_urb->sgt);
>                 uvc_urb->buffer = NULL;
>                 uvc_urb->sgt = NULL;
> @@ -1820,7 +1821,7 @@ static int uvc_alloc_urb_buffers(struct
> uvc_streaming *stream,
> 
>                         if (!uvc_alloc_urb_buffer(stream, uvc_urb, urb_size,
>                                                   gfp_flags)) {
> -                               uvc_free_urb_buffers(stream);
> +                               uvc_free_urb_buffers(stream, urb_size);
>                                 break;
>                         }
> 
> @@ -1868,7 +1869,7 @@ static void uvc_video_stop_transfer(struct
> uvc_streaming *stream,
>         }
> 
>         if (free_buffers)
> -               uvc_free_urb_buffers(stream);
> +               uvc_free_urb_buffers(stream, stream->urb_size);
>  }
> 
>  /*

I'm tempted to revert commit c824345288d1 ("media: uvcvideo: Pass
allocation size directly to uvc_alloc_urb_buffer") instead. It was
supposeed to be a pure refactoring without any functional change, and
adding this on top makes me feel the code is getting more complex as a
result.

> >
> >     [  739.196672] UBSAN: shift-out-of-bounds in /builddir/build/BUILD/kernel-latest-7.0-build/kernel-latest-7.0/linux-7.0-rc4/mm/page_alloc.c:1403:22
> >     [  739.196710] shift exponent 52 is too large for 32-bit type 'int'
> >     [  739.196730] CPU: 1 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full)
> >     [  739.196733] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
> >     [  739.196734] Call Trace:
> >     [  739.196737]  <TASK>
> >     [  739.196739]  dump_stack_lvl+0x5d/0x80
> >     [  739.196744]  ubsan_epilogue+0x5/0x2b
> >     [  739.196746]  __ubsan_handle_shift_out_of_bounds.cold+0x61/0xe6
> >     [  739.196749]  __free_pages_ok.cold+0x13/0xa8
> >     [  739.196753]  dma_free_noncontiguous+0xbf/0xe0
> >     [  739.196756]  ? usb_free_noncoherent+0x3a/0x60
> >     [  739.196761]  uvc_free_urb_buffers+0x38/0x90 [uvcvideo]
> >     [  739.196773]  uvc_alloc_urb_buffers.part.0+0xe6/0x130 [uvcvideo]
> >     [  739.196781]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
> >     [  739.196789]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
> >     [  739.196797]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
> >     [  739.196806]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
> >     [  739.196813]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
> >     [  739.196819]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
> >     [  739.196824]  __video_do_ioctl+0x419/0x540 [videodev]
> >     [  739.196847]  video_usercopy+0x23b/0x630 [videodev]
> >     [  739.196863]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
> >     [  739.196880]  v4l2_ioctl+0x6b/0xa0 [videodev]
> >     [  739.196895]  __x64_sys_ioctl+0x96/0xe0
> >     [  739.196898]  do_syscall_64+0x120/0x6c0
> >     [  739.196902]  ? do_read_fault+0xf5/0x220
> >     [  739.196906]  ? do_fault+0x148/0x270
> >     [  739.196908]  ? __handle_mm_fault+0x470/0x6c0
> >     [  739.196911]  ? count_memcg_events+0xeb/0x1b0
> >     [  739.196914]  ? handle_mm_fault+0x220/0x340
> >     [  739.196916]  ? do_user_addr_fault+0x1e5/0x7f0
> >     [  739.196920]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
> >     [  739.196924]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> >     [  739.196926] RIP: 0033:0x738e787000ed
> >     [  739.196929] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
> >     [  739.196930] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> >     [  739.196933] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX: 0000738e787000ed
> >     [  739.196934] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI: 0000000000000010
> >     [  739.196935] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09: 0000000000000000
> >     [  739.196936] R10: 0000738e6400ae30 R11: 0000000000000246 R12: 0000000000000000
> >     [  739.196937] R13: 0000738e640012d0 R14: 0000738e64008850 R15: 0000000000000002
> >     [  739.196939]  </TASK>
> >     [  739.196940] ---[ end trace ]---
> >     [  739.197835] BUG: Bad page state in process v4l2src0:src  pfn:009a0
> >     [  739.198028] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x2a pfn:0x9a0
> >     [  739.198054] flags: 0x7ffffc0000000(node=0|zone=0|lastcpupid=0x1fffff)
> >     [  739.198074] page_type: f0(buddy)
> >     [  739.198088] raw: 0007ffffc0000000 fffffac1c0026a08 fffffac1c0025e08 0000000000000000
> >     [  739.198111] raw: 000000000000002a 0000000000000002 00000000f0000000 0000000000000000
> >     [  739.198133] page dumped because: nonzero mapcount
> >     [  739.198149] Modules linked in: nft_reject_ipv6 nf_reject_ipv6 nft_reject_ipv4 nf_reject_ipv4 nft_reject nft_ct nft_masq nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables uvcvideo ath3k btusb btmtk uvc videobuf2_vmalloc btrtl videobuf2_memops videobuf2_v4l2 cdc_mbim btbcm cdc_ncm videobuf2_common btintel cdc_ether usbnet videodev bluetooth mii cdc_wdm mc rfkill cdc_acm joydev intel_rapl_msr intel_rapl_common ghash_clmulni_intel xhci_pci xhci_hcd ehci_pci ehci_hcd pcspkr i2c_piix4 ata_generic pata_acpi i2c_smbus serio_raw xen_scsiback target_core_mod xen_netback xen_privcmd xen_gntdev xen_gntalloc xen_blkback xen_evtchn i2c_dev fuse loop nfnetlink overlay xen_blkfront
> >     [  739.198472] CPU: 1 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full)
> >     [  739.198475] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
> >     [  739.198477] Call Trace:
> >     [  739.198479]  <TASK>
> >     [  739.198480]  dump_stack_lvl+0x5d/0x80
> >     [  739.198485]  bad_page.cold+0x7a/0x91
> >     [  739.198488]  __free_pages_ok+0x481/0x680
> >     [  739.198491]  dma_free_noncontiguous+0xbf/0xe0
> >     [  739.198494]  ? usb_free_noncoherent+0x3a/0x60
> >     [  739.198497]  uvc_free_urb_buffers+0x38/0x90 [uvcvideo]
> >     [  739.198507]  uvc_alloc_urb_buffers.part.0+0xe6/0x130 [uvcvideo]
> >     [  739.198515]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
> >     [  739.198523]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
> >     [  739.198531]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
> >     [  739.198539]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
> >     [  739.198546]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
> >     [  739.198551]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
> >     [  739.198555]  __video_do_ioctl+0x419/0x540 [videodev]
> >     [  739.198574]  video_usercopy+0x23b/0x630 [videodev]
> >     [  739.198590]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
> >     [  739.198607]  v4l2_ioctl+0x6b/0xa0 [videodev]
> >     [  739.198622]  __x64_sys_ioctl+0x96/0xe0
> >     [  739.198625]  do_syscall_64+0x120/0x6c0
> >     [  739.198629]  ? do_read_fault+0xf5/0x220
> >     [  739.198632]  ? do_fault+0x148/0x270
> >     [  739.198635]  ? __handle_mm_fault+0x470/0x6c0
> >     [  739.198637]  ? count_memcg_events+0xeb/0x1b0
> >     [  739.198640]  ? handle_mm_fault+0x220/0x340
> >     [  739.198642]  ? do_user_addr_fault+0x1e5/0x7f0
> >     [  739.198645]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
> >     [  739.198648]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> >     [  739.198651] RIP: 0033:0x738e787000ed
> >     [  739.198653] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
> >     [  739.198654] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> >     [  739.198656] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX: 0000738e787000ed
> >     [  739.198657] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI: 0000000000000010
> >     [  739.198658] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09: 0000000000000000
> >     [  739.198659] R10: 0000738e6400ae30 R11: 0000000000000246 R12: 0000000000000000
> >     [  739.198660] R13: 0000738e640012d0 R14: 0000738e64008850 R15: 0000000000000002
> >     [  739.198662]  </TASK>
> >     [  739.198663] Disabling lock debugging due to kernel taint
> >
> > And eventually kernel panic:
> >
> >     [  740.464422] BUG: unable to handle page fault for address: fffffac1c0800000
> >     [  740.464454] #PF: supervisor read access in kernel mode
> >     [  740.464471] #PF: error_code(0x0000) - not-present page
> >     [  740.464488] PGD 11be0067 P4D 11be0067 PUD 1148f067 PMD 0
> >
> > Full console log is at: https://gist.github.com/marmarek/5d839f419b1d56e71a48e74ae66f0e7a

-- 
Regards,

Laurent Pinchart

Re: Linux 7.0-rc4: v4l2src0:src: page allocation failure - increased memory usage in 7.0?

[Ricardo Ribalda]

Hi Laurent

On Fri, 20 Mar 2026 at 02:07, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Ricardo,
>
> On Thu, Mar 19, 2026 at 11:19:38AM +0100, Ricardo Ribalda wrote:
> > On Thu, 19 Mar 2026 at 01:18, Marek Marczykowski-Górecki wrote:
> > > Hello,
> > >
> > > When testing 7.0-rc4 (and also got it with 7.0-rc1), I got page
> > > allocation failure in uvcvideo when using v4l2 camera in a VM. The setup
> > > is rather memory constrained - it's a HVM with just 300MB of memory
> > > running on Xen, with PCI passthrough of USB controllers (to which an USB
> > > camera is connected). But the very same setup works just fine with older
> > > kernel (last known good is 6.19.5, built with the same config).
> > >
> > > I'm not exactly sure if uvcvideo is really to blame here, or is it just
> > > a victim of something else using more memory. Any advice how to check
> > > for that?
> >
> > I have looked at at:
> > git diff v6.19..linus/master drivers/media/usb/uvc/
> >
> > And I have not found anything that indicate me that we allocate more
> > memory or we allocate it differently.
> >
> > > The specific error is:
> > >
> > >     [  739.040844] systemd-journald[251]: Under memory pressure, flushing caches.
> > >     [  739.193589] v4l2src0:src: page allocation failure: order:5, mode:0xcc4(GFP_KERNEL|GFP_DMA32), nodemask=(null),cpuset=/,mems_allowed=0
> > >     [  739.193645] CPU: 0 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full)
> > >     [  739.193648] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
> > >     [  739.193649] Call Trace:
> > >     [  739.193652]  <TASK>
> > >     [  739.193656]  dump_stack_lvl+0x5d/0x80
> > >     [  739.193661]  warn_alloc+0x162/0x190
> > >     [  739.193665]  ? __alloc_pages_direct_compact+0x1bc/0x220
> > >     [  739.193669]  __alloc_pages_slowpath.constprop.0+0x4ea/0xb30
> > >     [  739.193672]  ? kernfs_activate+0x4c/0x60
> > >     [  739.193676]  __alloc_frozen_pages_noprof+0x2ff/0x340
> > >     [  739.193679]  __alloc_pages_noprof+0xe/0x20
> > >     [  739.193682]  __dma_direct_alloc_pages.isra.0+0x183/0x310
> > >     [  739.193688]  dma_direct_alloc_pages+0x3f/0x190
> > >     [  739.193693]  dma_alloc_noncontiguous+0xdd/0x290
> > >     [  739.193698]  ? usb_create_ep_devs+0xab/0x100
> > >     [  739.193701]  usb_alloc_noncoherent+0x45/0xa0
> > >     [  739.193709]  uvc_alloc_urb_buffers.part.0+0x93/0x130 [uvcvideo]
> > >     [  739.193722]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
> > >     [  739.193735]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
> > >     [  739.193744]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
> > >     [  739.193752]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
> > >     [  739.193761]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
> > >     [  739.193767]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
> > >     [  739.193773]  __video_do_ioctl+0x419/0x540 [videodev]
> > >     [  739.193799]  video_usercopy+0x23b/0x630 [videodev]
> > >     [  739.193819]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
> > >     [  739.193836]  v4l2_ioctl+0x6b/0xa0 [videodev]
> > >     [  739.193851]  __x64_sys_ioctl+0x96/0xe0
> > >     [  739.193855]  do_syscall_64+0x120/0x6c0
> > >     [  739.193859]  ? do_read_fault+0xf5/0x220
> > >     [  739.193863]  ? do_fault+0x148/0x270
> > >     [  739.193865]  ? __handle_mm_fault+0x470/0x6c0
> > >     [  739.193868]  ? count_memcg_events+0xeb/0x1b0
> > >     [  739.193871]  ? handle_mm_fault+0x220/0x340
> > >     [  739.193873]  ? do_user_addr_fault+0x1e5/0x7f0
> > >     [  739.193876]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
> > >     [  739.193880]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> > >     [  739.193883] RIP: 0033:0x738e787000ed
> > >     [  739.193886] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
> > >     [  739.193888] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> > >     [  739.193890] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX: 0000738e787000ed
> > >     [  739.193892] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI: 0000000000000010
> > >     [  739.193893] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09: 0000000000000000
> > >     [  739.193894] R10: 0000738e6400ae30 R11: 0000000000000246 R12: 0000000000000000
> > >     [  739.193895] R13: 0000738e640012d0 R14: 0000738e64008850 R15: 0000000000000002
> > >     [  739.193897]  </TASK>
> > >     [  739.193907] Mem-Info:
> > >     [  739.194897] active_anon:362 inactive_anon:3172 isolated_anon:0
> > >     [  739.194897]  active_file:2498 inactive_file:11687 isolated_file:1
> > >     [  739.194897]  unevictable:0 dirty:0 writeback:4
> > >     [  739.194897]  slab_reclaimable:3707 slab_unreclaimable:10022
> > >     [  739.194897]  mapped:4710 shmem:9 pagetables:1021
> > >     [  739.194897]  sec_pagetables:0 bounce:0
> > >     [  739.194897]  kernel_misc_reclaimable:0
> > >     [  739.194897]  free:3452 free_pcp:1 free_cma:0
> > >     [  739.195008] Node 0 active_anon:1448kB inactive_anon:12688kB active_file:9992kB inactive_file:46748kB unevictable:0kB isolated(anon):0kB isolated(file):4kB mapped:18840kB dirty:0kB writeback:16kB shmem:36kB shmem_thp:0kB shmem_pmdmapped:0kB anon_thp:0kB kernel_stack:2416kB pagetables:4084kB sec_pagetables:0kB all_unreclaimable? no Balloon:16384kB
> > >     [  739.195097] Node 0 DMA free:2828kB boost:0kB min:132kB low:164kB high:196kB reserved_highatomic:0KB free_highatomic:0KB active_anon:224kB inactive_anon:940kB active_file:1360kB inactive_file:2408kB unevictable:0kB writepending:0kB zspages:0kB present:15992kB managed:15360kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> > >     [  739.195186] lowmem_reserve[]: 0 195 195 195 195
> > >     [  739.196280] Node 0 DMA32 free:14880kB boost:3856kB min:5572kB low:6000kB high:6428kB reserved_highatomic:0KB free_highatomic:0KB active_anon:1224kB inactive_anon:11728kB active_file:8632kB inactive_file:40024kB unevictable:0kB writepending:16kB zspages:0kB present:274348kB managed:200080kB mlocked:0kB bounce:0kB free_pcp:316kB local_pcp:236kB free_cma:0kB
> > >     [  739.196372] lowmem_reserve[]: 0 0 0 0 0
> > >     [  739.196388] Node 0 DMA: 193*4kB (UM) 213*8kB (UM) 22*16kB (UM) 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 2828kB
> > >     [  739.196433] Node 0 DMA32: 1631*4kB (UME) 764*8kB (UME) 138*16kB (UME) 8*32kB (UM) 3*64kB (M) 1*128kB (M) 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 15420kB
> > >     [  739.196487] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
> > >     [  739.196514] 14914 total pagecache pages
> > >     [  739.196527] 2073 pages in swap cache
> > >     [  739.196539] Free swap  = 961672kB
> > >     [  739.196551] Total swap = 1048572kB
> > >     [  739.196563] 72585 pages RAM
> > >     [  739.196572] 0 pages HighMem/MovableOnly
> > >     [  739.196584] 18725 pages reserved
> > >     [  739.196596] 0 pages cma reserved
> > >     [  739.196608] 0 pages hwpoisoned
> > >     [  739.196620] Memory cgroup min protection 0kB -- low protection 0kB
> > >     [  739.196627] ------------[ cut here ]------------
> > >
> > > Additionally, this failure isn't handled gracefully, it's followed with:
> >
> > That should not happen.... Could you check if this fixes it:
> >
> > diff --git a/drivers/media/usb/uvc/uvc_video.c
> > b/drivers/media/usb/uvc/uvc_video.c
> > index 40c76c051da2..f6c8e3223796 100644
> > --- a/drivers/media/usb/uvc/uvc_video.c
> > +++ b/drivers/media/usb/uvc/uvc_video.c
> > @@ -1751,7 +1751,8 @@ static void uvc_video_complete(struct urb *urb)
> >  /*
> >   * Free transfer buffers.
> >   */
> > -static void uvc_free_urb_buffers(struct uvc_streaming *stream)
> > +static void uvc_free_urb_buffers(struct uvc_streaming *stream,
> > +                                unsigned int size)
> >  {
> >         struct usb_device *udev = stream->dev->udev;
> >         struct uvc_urb *uvc_urb;
> > @@ -1760,7 +1761,7 @@ static void uvc_free_urb_buffers(struct
> > uvc_streaming *stream)
> >                 if (!uvc_urb->buffer)
> >                         continue;
> >
> > -               usb_free_noncoherent(udev, stream->urb_size, uvc_urb->buffer,
> > +               usb_free_noncoherent(udev, size, uvc_urb->buffer,
> >                                      uvc_stream_dir(stream), uvc_urb->sgt);
> >                 uvc_urb->buffer = NULL;
> >                 uvc_urb->sgt = NULL;
> > @@ -1820,7 +1821,7 @@ static int uvc_alloc_urb_buffers(struct
> > uvc_streaming *stream,
> >
> >                         if (!uvc_alloc_urb_buffer(stream, uvc_urb, urb_size,
> >                                                   gfp_flags)) {
> > -                               uvc_free_urb_buffers(stream);
> > +                               uvc_free_urb_buffers(stream, urb_size);
> >                                 break;
> >                         }
> >
> > @@ -1868,7 +1869,7 @@ static void uvc_video_stop_transfer(struct
> > uvc_streaming *stream,
> >         }
> >
> >         if (free_buffers)
> > -               uvc_free_urb_buffers(stream);
> > +               uvc_free_urb_buffers(stream, stream->urb_size);
> >  }
> >
> >  /*
>
> I'm tempted to revert commit c824345288d1 ("media: uvcvideo: Pass
> allocation size directly to uvc_alloc_urb_buffer") instead. It was
> supposeed to be a pure refactoring without any functional change, and
> adding this on top makes me feel the code is getting more complex as a
> result.

I think this patch is more robust. Relying on a temporary value of
stream->urb_size can lead to errors.
But I am of course biased :)

I have sent a patch to the ML, please feel free to either go with the
revert route or review that patch.

Thanks!

>
> > >
> > >     [  739.196672] UBSAN: shift-out-of-bounds in /builddir/build/BUILD/kernel-latest-7.0-build/kernel-latest-7.0/linux-7.0-rc4/mm/page_alloc.c:1403:22
> > >     [  739.196710] shift exponent 52 is too large for 32-bit type 'int'
> > >     [  739.196730] CPU: 1 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full)
> > >     [  739.196733] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
> > >     [  739.196734] Call Trace:
> > >     [  739.196737]  <TASK>
> > >     [  739.196739]  dump_stack_lvl+0x5d/0x80
> > >     [  739.196744]  ubsan_epilogue+0x5/0x2b
> > >     [  739.196746]  __ubsan_handle_shift_out_of_bounds.cold+0x61/0xe6
> > >     [  739.196749]  __free_pages_ok.cold+0x13/0xa8
> > >     [  739.196753]  dma_free_noncontiguous+0xbf/0xe0
> > >     [  739.196756]  ? usb_free_noncoherent+0x3a/0x60
> > >     [  739.196761]  uvc_free_urb_buffers+0x38/0x90 [uvcvideo]
> > >     [  739.196773]  uvc_alloc_urb_buffers.part.0+0xe6/0x130 [uvcvideo]
> > >     [  739.196781]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
> > >     [  739.196789]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
> > >     [  739.196797]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
> > >     [  739.196806]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
> > >     [  739.196813]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
> > >     [  739.196819]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
> > >     [  739.196824]  __video_do_ioctl+0x419/0x540 [videodev]
> > >     [  739.196847]  video_usercopy+0x23b/0x630 [videodev]
> > >     [  739.196863]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
> > >     [  739.196880]  v4l2_ioctl+0x6b/0xa0 [videodev]
> > >     [  739.196895]  __x64_sys_ioctl+0x96/0xe0
> > >     [  739.196898]  do_syscall_64+0x120/0x6c0
> > >     [  739.196902]  ? do_read_fault+0xf5/0x220
> > >     [  739.196906]  ? do_fault+0x148/0x270
> > >     [  739.196908]  ? __handle_mm_fault+0x470/0x6c0
> > >     [  739.196911]  ? count_memcg_events+0xeb/0x1b0
> > >     [  739.196914]  ? handle_mm_fault+0x220/0x340
> > >     [  739.196916]  ? do_user_addr_fault+0x1e5/0x7f0
> > >     [  739.196920]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
> > >     [  739.196924]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> > >     [  739.196926] RIP: 0033:0x738e787000ed
> > >     [  739.196929] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
> > >     [  739.196930] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> > >     [  739.196933] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX: 0000738e787000ed
> > >     [  739.196934] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI: 0000000000000010
> > >     [  739.196935] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09: 0000000000000000
> > >     [  739.196936] R10: 0000738e6400ae30 R11: 0000000000000246 R12: 0000000000000000
> > >     [  739.196937] R13: 0000738e640012d0 R14: 0000738e64008850 R15: 0000000000000002
> > >     [  739.196939]  </TASK>
> > >     [  739.196940] ---[ end trace ]---
> > >     [  739.197835] BUG: Bad page state in process v4l2src0:src  pfn:009a0
> > >     [  739.198028] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x2a pfn:0x9a0
> > >     [  739.198054] flags: 0x7ffffc0000000(node=0|zone=0|lastcpupid=0x1fffff)
> > >     [  739.198074] page_type: f0(buddy)
> > >     [  739.198088] raw: 0007ffffc0000000 fffffac1c0026a08 fffffac1c0025e08 0000000000000000
> > >     [  739.198111] raw: 000000000000002a 0000000000000002 00000000f0000000 0000000000000000
> > >     [  739.198133] page dumped because: nonzero mapcount
> > >     [  739.198149] Modules linked in: nft_reject_ipv6 nf_reject_ipv6 nft_reject_ipv4 nf_reject_ipv4 nft_reject nft_ct nft_masq nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables uvcvideo ath3k btusb btmtk uvc videobuf2_vmalloc btrtl videobuf2_memops videobuf2_v4l2 cdc_mbim btbcm cdc_ncm videobuf2_common btintel cdc_ether usbnet videodev bluetooth mii cdc_wdm mc rfkill cdc_acm joydev intel_rapl_msr intel_rapl_common ghash_clmulni_intel xhci_pci xhci_hcd ehci_pci ehci_hcd pcspkr i2c_piix4 ata_generic pata_acpi i2c_smbus serio_raw xen_scsiback target_core_mod xen_netback xen_privcmd xen_gntdev xen_gntalloc xen_blkback xen_evtchn i2c_dev fuse loop nfnetlink overlay xen_blkfront
> > >     [  739.198472] CPU: 1 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full)
> > >     [  739.198475] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
> > >     [  739.198477] Call Trace:
> > >     [  739.198479]  <TASK>
> > >     [  739.198480]  dump_stack_lvl+0x5d/0x80
> > >     [  739.198485]  bad_page.cold+0x7a/0x91
> > >     [  739.198488]  __free_pages_ok+0x481/0x680
> > >     [  739.198491]  dma_free_noncontiguous+0xbf/0xe0
> > >     [  739.198494]  ? usb_free_noncoherent+0x3a/0x60
> > >     [  739.198497]  uvc_free_urb_buffers+0x38/0x90 [uvcvideo]
> > >     [  739.198507]  uvc_alloc_urb_buffers.part.0+0xe6/0x130 [uvcvideo]
> > >     [  739.198515]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
> > >     [  739.198523]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
> > >     [  739.198531]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
> > >     [  739.198539]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
> > >     [  739.198546]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
> > >     [  739.198551]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
> > >     [  739.198555]  __video_do_ioctl+0x419/0x540 [videodev]
> > >     [  739.198574]  video_usercopy+0x23b/0x630 [videodev]
> > >     [  739.198590]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
> > >     [  739.198607]  v4l2_ioctl+0x6b/0xa0 [videodev]
> > >     [  739.198622]  __x64_sys_ioctl+0x96/0xe0
> > >     [  739.198625]  do_syscall_64+0x120/0x6c0
> > >     [  739.198629]  ? do_read_fault+0xf5/0x220
> > >     [  739.198632]  ? do_fault+0x148/0x270
> > >     [  739.198635]  ? __handle_mm_fault+0x470/0x6c0
> > >     [  739.198637]  ? count_memcg_events+0xeb/0x1b0
> > >     [  739.198640]  ? handle_mm_fault+0x220/0x340
> > >     [  739.198642]  ? do_user_addr_fault+0x1e5/0x7f0
> > >     [  739.198645]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
> > >     [  739.198648]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> > >     [  739.198651] RIP: 0033:0x738e787000ed
> > >     [  739.198653] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45 b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
> > >     [  739.198654] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> > >     [  739.198656] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX: 0000738e787000ed
> > >     [  739.198657] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI: 0000000000000010
> > >     [  739.198658] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09: 0000000000000000
> > >     [  739.198659] R10: 0000738e6400ae30 R11: 0000000000000246 R12: 0000000000000000
> > >     [  739.198660] R13: 0000738e640012d0 R14: 0000738e64008850 R15: 0000000000000002
> > >     [  739.198662]  </TASK>
> > >     [  739.198663] Disabling lock debugging due to kernel taint
> > >
> > > And eventually kernel panic:
> > >
> > >     [  740.464422] BUG: unable to handle page fault for address: fffffac1c0800000
> > >     [  740.464454] #PF: supervisor read access in kernel mode
> > >     [  740.464471] #PF: error_code(0x0000) - not-present page
> > >     [  740.464488] PGD 11be0067 P4D 11be0067 PUD 1148f067 PMD 0
> > >
> > > Full console log is at: https://gist.github.com/marmarek/5d839f419b1d56e71a48e74ae66f0e7a
>
> --
> Regards,
>
> Laurent Pinchart



-- 
Ricardo Ribalda

Re: Linux 7.0-rc4: v4l2src0:src: page allocation failure - increased memory usage in 7.0?

[Nicolas Dufresne]

[-- Attachment #1: Type: text/plain, Size: 15558 bytes --]

Hi,

Le jeudi 19 mars 2026 à 01:18 +0100, Marek Marczykowski-Górecki a écrit :
> Hello,
> 
> When testing 7.0-rc4 (and also got it with 7.0-rc1), I got page
> allocation failure in uvcvideo when using v4l2 camera in a VM. The setup
> is rather memory constrained - it's a HVM with just 300MB of memory
> running on Xen, with PCI passthrough of USB controllers (to which an USB
> camera is connected). But the very same setup works just fine with older
> kernel (last known good is 6.19.5, built with the same config).
> 
> I'm not exactly sure if uvcvideo is really to blame here, or is it just
> a victim of something else using more memory. Any advice how to check
> for that?

I've seen the same backtrace this morning but on 6.19.7-200.fc43.x86_64 and
through Pipewire instead of GStreamer. I think that rules out the userspace. To
me it seems quite likely a UVC regression that got backported).

Nicolas

> 
> The specific error is:
> 
>     [  739.040844] systemd-journald[251]: Under memory pressure, flushing
> caches.
>     [  739.193589] v4l2src0:src: page allocation failure: order:5,
> mode:0xcc4(GFP_KERNEL|GFP_DMA32), nodemask=(null),cpuset=/,mems_allowed=0
>     [  739.193645] CPU: 0 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted
> 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full) 
>     [  739.193648] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
>     [  739.193649] Call Trace:
>     [  739.193652]  <TASK>
>     [  739.193656]  dump_stack_lvl+0x5d/0x80
>     [  739.193661]  warn_alloc+0x162/0x190
>     [  739.193665]  ? __alloc_pages_direct_compact+0x1bc/0x220
>     [  739.193669]  __alloc_pages_slowpath.constprop.0+0x4ea/0xb30
>     [  739.193672]  ? kernfs_activate+0x4c/0x60
>     [  739.193676]  __alloc_frozen_pages_noprof+0x2ff/0x340
>     [  739.193679]  __alloc_pages_noprof+0xe/0x20
>     [  739.193682]  __dma_direct_alloc_pages.isra.0+0x183/0x310
>     [  739.193688]  dma_direct_alloc_pages+0x3f/0x190
>     [  739.193693]  dma_alloc_noncontiguous+0xdd/0x290
>     [  739.193698]  ? usb_create_ep_devs+0xab/0x100
>     [  739.193701]  usb_alloc_noncoherent+0x45/0xa0
>     [  739.193709]  uvc_alloc_urb_buffers.part.0+0x93/0x130 [uvcvideo]
>     [  739.193722]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
>     [  739.193735]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
>     [  739.193744]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
>     [  739.193752]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
>     [  739.193761]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
>     [  739.193767]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
>     [  739.193773]  __video_do_ioctl+0x419/0x540 [videodev]
>     [  739.193799]  video_usercopy+0x23b/0x630 [videodev]
>     [  739.193819]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
>     [  739.193836]  v4l2_ioctl+0x6b/0xa0 [videodev]
>     [  739.193851]  __x64_sys_ioctl+0x96/0xe0
>     [  739.193855]  do_syscall_64+0x120/0x6c0
>     [  739.193859]  ? do_read_fault+0xf5/0x220
>     [  739.193863]  ? do_fault+0x148/0x270
>     [  739.193865]  ? __handle_mm_fault+0x470/0x6c0
>     [  739.193868]  ? count_memcg_events+0xeb/0x1b0
>     [  739.193871]  ? handle_mm_fault+0x220/0x340
>     [  739.193873]  ? do_user_addr_fault+0x1e5/0x7f0
>     [  739.193876]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
>     [  739.193880]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
>     [  739.193883] RIP: 0033:0x738e787000ed
>     [  739.193886] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45
> b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89>
> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
>     [  739.193888] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX:
> 0000000000000010
>     [  739.193890] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX:
> 0000738e787000ed
>     [  739.193892] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI:
> 0000000000000010
>     [  739.193893] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09:
> 0000000000000000
>     [  739.193894] R10: 0000738e6400ae30 R11: 0000000000000246 R12:
> 0000000000000000
>     [  739.193895] R13: 0000738e640012d0 R14: 0000738e64008850 R15:
> 0000000000000002
>     [  739.193897]  </TASK>
>     [  739.193907] Mem-Info:
>     [  739.194897] active_anon:362 inactive_anon:3172 isolated_anon:0
>     [  739.194897]  active_file:2498 inactive_file:11687 isolated_file:1
>     [  739.194897]  unevictable:0 dirty:0 writeback:4
>     [  739.194897]  slab_reclaimable:3707 slab_unreclaimable:10022
>     [  739.194897]  mapped:4710 shmem:9 pagetables:1021
>     [  739.194897]  sec_pagetables:0 bounce:0
>     [  739.194897]  kernel_misc_reclaimable:0
>     [  739.194897]  free:3452 free_pcp:1 free_cma:0
>     [  739.195008] Node 0 active_anon:1448kB inactive_anon:12688kB
> active_file:9992kB inactive_file:46748kB unevictable:0kB isolated(anon):0kB
> isolated(file):4kB mapped:18840kB dirty:0kB writeback:16kB shmem:36kB
> shmem_thp:0kB shmem_pmdmapped:0kB anon_thp:0kB kernel_stack:2416kB
> pagetables:4084kB sec_pagetables:0kB all_unreclaimable? no Balloon:16384kB
>     [  739.195097] Node 0 DMA free:2828kB boost:0kB min:132kB low:164kB
> high:196kB reserved_highatomic:0KB free_highatomic:0KB active_anon:224kB
> inactive_anon:940kB active_file:1360kB inactive_file:2408kB unevictable:0kB
> writepending:0kB zspages:0kB present:15992kB managed:15360kB mlocked:0kB
> bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>     [  739.195186] lowmem_reserve[]: 0 195 195 195 195
>     [  739.196280] Node 0 DMA32 free:14880kB boost:3856kB min:5572kB
> low:6000kB high:6428kB reserved_highatomic:0KB free_highatomic:0KB
> active_anon:1224kB inactive_anon:11728kB active_file:8632kB
> inactive_file:40024kB unevictable:0kB writepending:16kB zspages:0kB
> present:274348kB managed:200080kB mlocked:0kB bounce:0kB free_pcp:316kB
> local_pcp:236kB free_cma:0kB
>     [  739.196372] lowmem_reserve[]: 0 0 0 0 0
>     [  739.196388] Node 0 DMA: 193*4kB (UM) 213*8kB (UM) 22*16kB (UM) 0*32kB
> 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 2828kB
>     [  739.196433] Node 0 DMA32: 1631*4kB (UME) 764*8kB (UME) 138*16kB (UME)
> 8*32kB (UM) 3*64kB (M) 1*128kB (M) 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB
> = 15420kB
>     [  739.196487] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0
> hugepages_size=2048kB
>     [  739.196514] 14914 total pagecache pages
>     [  739.196527] 2073 pages in swap cache
>     [  739.196539] Free swap  = 961672kB
>     [  739.196551] Total swap = 1048572kB
>     [  739.196563] 72585 pages RAM
>     [  739.196572] 0 pages HighMem/MovableOnly
>     [  739.196584] 18725 pages reserved
>     [  739.196596] 0 pages cma reserved
>     [  739.196608] 0 pages hwpoisoned
>     [  739.196620] Memory cgroup min protection 0kB -- low protection 0kB
>     [  739.196627] ------------[ cut here ]------------
> 
> Additionally, this failure isn't handled gracefully, it's followed with:
> 
>     [  739.196672] UBSAN: shift-out-of-bounds in /builddir/build/BUILD/kernel-
> latest-7.0-build/kernel-latest-7.0/linux-7.0-rc4/mm/page_alloc.c:1403:22
>     [  739.196710] shift exponent 52 is too large for 32-bit type 'int'
>     [  739.196730] CPU: 1 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted
> 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full) 
>     [  739.196733] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
>     [  739.196734] Call Trace:
>     [  739.196737]  <TASK>
>     [  739.196739]  dump_stack_lvl+0x5d/0x80
>     [  739.196744]  ubsan_epilogue+0x5/0x2b
>     [  739.196746]  __ubsan_handle_shift_out_of_bounds.cold+0x61/0xe6
>     [  739.196749]  __free_pages_ok.cold+0x13/0xa8
>     [  739.196753]  dma_free_noncontiguous+0xbf/0xe0
>     [  739.196756]  ? usb_free_noncoherent+0x3a/0x60
>     [  739.196761]  uvc_free_urb_buffers+0x38/0x90 [uvcvideo]
>     [  739.196773]  uvc_alloc_urb_buffers.part.0+0xe6/0x130 [uvcvideo]
>     [  739.196781]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
>     [  739.196789]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
>     [  739.196797]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
>     [  739.196806]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
>     [  739.196813]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
>     [  739.196819]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
>     [  739.196824]  __video_do_ioctl+0x419/0x540 [videodev]
>     [  739.196847]  video_usercopy+0x23b/0x630 [videodev]
>     [  739.196863]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
>     [  739.196880]  v4l2_ioctl+0x6b/0xa0 [videodev]
>     [  739.196895]  __x64_sys_ioctl+0x96/0xe0
>     [  739.196898]  do_syscall_64+0x120/0x6c0
>     [  739.196902]  ? do_read_fault+0xf5/0x220
>     [  739.196906]  ? do_fault+0x148/0x270
>     [  739.196908]  ? __handle_mm_fault+0x470/0x6c0
>     [  739.196911]  ? count_memcg_events+0xeb/0x1b0
>     [  739.196914]  ? handle_mm_fault+0x220/0x340
>     [  739.196916]  ? do_user_addr_fault+0x1e5/0x7f0
>     [  739.196920]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
>     [  739.196924]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
>     [  739.196926] RIP: 0033:0x738e787000ed
>     [  739.196929] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45
> b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89>
> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
>     [  739.196930] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX:
> 0000000000000010
>     [  739.196933] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX:
> 0000738e787000ed
>     [  739.196934] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI:
> 0000000000000010
>     [  739.196935] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09:
> 0000000000000000
>     [  739.196936] R10: 0000738e6400ae30 R11: 0000000000000246 R12:
> 0000000000000000
>     [  739.196937] R13: 0000738e640012d0 R14: 0000738e64008850 R15:
> 0000000000000002
>     [  739.196939]  </TASK>
>     [  739.196940] ---[ end trace ]---
>     [  739.197835] BUG: Bad page state in process v4l2src0:src  pfn:009a0
>     [  739.198028] page: refcount:0 mapcount:0 mapping:0000000000000000
> index:0x2a pfn:0x9a0
>     [  739.198054] flags: 0x7ffffc0000000(node=0|zone=0|lastcpupid=0x1fffff)
>     [  739.198074] page_type: f0(buddy)
>     [  739.198088] raw: 0007ffffc0000000 fffffac1c0026a08 fffffac1c0025e08
> 0000000000000000
>     [  739.198111] raw: 000000000000002a 0000000000000002 00000000f0000000
> 0000000000000000
>     [  739.198133] page dumped because: nonzero mapcount
>     [  739.198149] Modules linked in: nft_reject_ipv6 nf_reject_ipv6
> nft_reject_ipv4 nf_reject_ipv4 nft_reject nft_ct nft_masq nft_chain_nat nf_nat
> nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables uvcvideo ath3k btusb
> btmtk uvc videobuf2_vmalloc btrtl videobuf2_memops videobuf2_v4l2 cdc_mbim
> btbcm cdc_ncm videobuf2_common btintel cdc_ether usbnet videodev bluetooth mii
> cdc_wdm mc rfkill cdc_acm joydev intel_rapl_msr intel_rapl_common
> ghash_clmulni_intel xhci_pci xhci_hcd ehci_pci ehci_hcd pcspkr i2c_piix4
> ata_generic pata_acpi i2c_smbus serio_raw xen_scsiback target_core_mod
> xen_netback xen_privcmd xen_gntdev xen_gntalloc xen_blkback xen_evtchn i2c_dev
> fuse loop nfnetlink overlay xen_blkfront
>     [  739.198472] CPU: 1 UID: 1000 PID: 1305 Comm: v4l2src0:src Not tainted
> 7.0.0-0.rc4.1.qubes.1001.fc41.x86_64 #1 PREEMPT(full) 
>     [  739.198475] Hardware name: Xen HVM domU, BIOS 4.19.4 03/17/2026
>     [  739.198477] Call Trace:
>     [  739.198479]  <TASK>
>     [  739.198480]  dump_stack_lvl+0x5d/0x80
>     [  739.198485]  bad_page.cold+0x7a/0x91
>     [  739.198488]  __free_pages_ok+0x481/0x680
>     [  739.198491]  dma_free_noncontiguous+0xbf/0xe0
>     [  739.198494]  ? usb_free_noncoherent+0x3a/0x60
>     [  739.198497]  uvc_free_urb_buffers+0x38/0x90 [uvcvideo]
>     [  739.198507]  uvc_alloc_urb_buffers.part.0+0xe6/0x130 [uvcvideo]
>     [  739.198515]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
>     [  739.198523]  uvc_video_start_streaming+0xab/0x100 [uvcvideo]
>     [  739.198531]  uvc_start_streaming_video+0xec/0x110 [uvcvideo]
>     [  739.198539]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
>     [  739.198546]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
>     [  739.198551]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
>     [  739.198555]  __video_do_ioctl+0x419/0x540 [videodev]
>     [  739.198574]  video_usercopy+0x23b/0x630 [videodev]
>     [  739.198590]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
>     [  739.198607]  v4l2_ioctl+0x6b/0xa0 [videodev]
>     [  739.198622]  __x64_sys_ioctl+0x96/0xe0
>     [  739.198625]  do_syscall_64+0x120/0x6c0
>     [  739.198629]  ? do_read_fault+0xf5/0x220
>     [  739.198632]  ? do_fault+0x148/0x270
>     [  739.198635]  ? __handle_mm_fault+0x470/0x6c0
>     [  739.198637]  ? count_memcg_events+0xeb/0x1b0
>     [  739.198640]  ? handle_mm_fault+0x220/0x340
>     [  739.198642]  ? do_user_addr_fault+0x1e5/0x7f0
>     [  739.198645]  ? arch_exit_to_user_mode_prepare.isra.0+0x9f/0xe0
>     [  739.198648]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
>     [  739.198651] RIP: 0033:0x738e787000ed
>     [  739.198653] Code: 04 25 28 00 00 00 48 89 45 c8 31 c0 48 8d 45 10 c7 45
> b0 10 00 00 00 48 89 45 b8 48 8d 45 d0 48 89 45 c0 b8 10 00 00 00 0f 05 <89>
> c2 3d 00 f0 ff ff 77 1a 48 8b 45 c8 64 48 2b 04 25 28 00 00 00
>     [  739.198654] RSP: 002b:0000738e730e6a00 EFLAGS: 00000246 ORIG_RAX:
> 0000000000000010
>     [  739.198656] RAX: ffffffffffffffda RBX: 0000738e64008850 RCX:
> 0000738e787000ed
>     [  739.198657] RDX: 000059d3df721cf0 RSI: 0000000040045612 RDI:
> 0000000000000010
>     [  739.198658] RBP: 0000738e730e6a50 R08: 0000738e6400ae40 R09:
> 0000000000000000
>     [  739.198659] R10: 0000738e6400ae30 R11: 0000000000000246 R12:
> 0000000000000000
>     [  739.198660] R13: 0000738e640012d0 R14: 0000738e64008850 R15:
> 0000000000000002
>     [  739.198662]  </TASK>
>     [  739.198663] Disabling lock debugging due to kernel taint
> 
> And eventually kernel panic:
> 
>     [  740.464422] BUG: unable to handle page fault for address:
> fffffac1c0800000
>     [  740.464454] #PF: supervisor read access in kernel mode
>     [  740.464471] #PF: error_code(0x0000) - not-present page
>     [  740.464488] PGD 11be0067 P4D 11be0067 PUD 1148f067 PMD 0 
> 
> Full console log is at:
> https://gist.github.com/marmarek/5d839f419b1d56e71a48e74ae66f0e7a

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Re: Linux 7.0-rc4: v4l2src0:src: page allocation failure - increased memory usage in 7.0?

[Harry Yoo]

On Thu, Mar 19, 2026 at 01:18:18AM +0100, Marek Marczykowski-Górecki wrote:
> Hello,
> 
> When testing 7.0-rc4 (and also got it with 7.0-rc1), I got page
> allocation failure in uvcvideo when using v4l2 camera in a VM. The setup
> is rather memory constrained - it's a HVM with just 300MB of memory
> running on Xen, with PCI passthrough of USB controllers (to which an USB
> camera is connected). But the very same setup works just fine with older
> kernel (last known good is 6.19.5, built with the same config).

Could you please share what /proc/meminfo looks like on v6.19, and
also enable memory allocation profiling feature [1] and see
what has changed between v6.19 and v7.0?

On v6.19, you should be able to see how much memory is allocated by
reading /proc/allocinfo.

On v7.0-rc4, warn_alloc() should let memory allocation profiling
print top users.

[1] https://docs.kernel.org/mm/allocation-profiling.html

-- 
Cheers,
Harry / Hyeonggon

Re: Linux 7.0-rc4: v4l2src0:src: page allocation failure - increased memory usage in 7.0?

[Marek Marczykowski-Górecki]

[-- Attachment #1: Type: text/plain, Size: 7783 bytes --]

On Fri, Mar 20, 2026 at 10:01:33AM +0900, Harry Yoo wrote:
> On Thu, Mar 19, 2026 at 01:18:18AM +0100, Marek Marczykowski-Górecki wrote:
> > Hello,
> > 
> > When testing 7.0-rc4 (and also got it with 7.0-rc1), I got page
> > allocation failure in uvcvideo when using v4l2 camera in a VM. The setup
> > is rather memory constrained - it's a HVM with just 300MB of memory
> > running on Xen, with PCI passthrough of USB controllers (to which an USB
> > camera is connected). But the very same setup works just fine with older
> > kernel (last known good is 6.19.5, built with the same config).
> 
> Could you please share what /proc/meminfo looks like on v6.19, and
> also enable memory allocation profiling feature [1] and see
> what has changed between v6.19 and v7.0?
> 
> On v6.19, you should be able to see how much memory is allocated by
> reading /proc/allocinfo.
> 
> On v7.0-rc4, warn_alloc() should let memory allocation profiling
> print top users.
> 
> [1] https://docs.kernel.org/mm/allocation-profiling.html

Thanks, this got me some more info (below). That said, I think I spoke
too soon about 6.19.5 - the page allocation failure happens there too,
just without follow up crash, and v4l2 generally works afterwards (maybe
few initial frames got lost? not sure) - so, I haven't noticed it
before. So, it doesn't look like increased memory usage anymore.

The message:

[   30.986973] v4l2src0:src: page allocation failure: order:5, mode:0xcc0(GFP_KERNEL), nodemask=(null),cpuset=/,mems_allowed=0
[   30.987035] CPU: 1 UID: 1000 PID: 1256 Comm: v4l2src0:src Not tainted 6.19.5-1.qubes.42.fc41.x86_64 #1 PREEMPT(full) 
[   30.987038] Hardware name: Xen HVM domU, BIOS 4.19.4 02/20/2026
[   30.987039] Call Trace:
[   30.987041]  <TASK>
[   30.987044]  dump_stack_lvl+0x5d/0x80
[   30.987049]  warn_alloc+0x162/0x190
[   30.987052]  ? __alloc_pages_direct_compact+0x1bc/0x220
[   30.987054]  __alloc_pages_slowpath.constprop.0+0x566/0x9b0
[   30.987056]  ? kernfs_next_descendant_post+0x1b/0xe0
[   30.987059]  __alloc_frozen_pages_noprof+0x31b/0x330
[   30.987062]  __alloc_pages_noprof+0xe/0x20
[   30.987063]  __dma_direct_alloc_pages.isra.0+0x1b2/0x3b0
[   30.987066]  dma_direct_alloc_pages+0x3f/0x190
[   30.987068]  alloc_single_sgt+0x12a/0x200
[   30.987071]  dma_alloc_noncontiguous+0x49/0x150
[   30.987074]  usb_alloc_noncoherent+0x45/0xa0
[   30.987079]  uvc_alloc_urb_buffers.part.0+0x95/0x130 [uvcvideo]
[   30.987092]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
[   30.987100]  uvc_video_start_streaming+0x9c/0x140 [uvcvideo]
[   30.987107]  uvc_start_streaming_video+0x58/0x100 [uvcvideo]
[   30.987116]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
[   30.987123]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
[   30.987128]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
[   30.987133]  __video_do_ioctl+0x419/0x540 [videodev]
[   30.987155]  video_usercopy+0x286/0x690 [videodev]
[   30.987168]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
[   30.987181]  v4l2_ioctl+0x6b/0xa0 [videodev]
[   30.987194]  __x64_sys_ioctl+0x96/0xe0
[   30.987198]  do_syscall_64+0x84/0x6c0
[   30.987201]  ? __handle_mm_fault+0x470/0x700
[   30.987204]  ? count_memcg_events+0xdd/0x1a0
[   30.987207]  ? handle_mm_fault+0x220/0x340
[   30.987209]  ? do_user_addr_fault+0x2c3/0x7f0
[   30.987212]  ? irqentry_exit+0x7a/0x510
[   30.987214]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[   30.987216] RIP: 0033:0x7953bd8838db
[   30.987219] Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
[   30.987220] RSP: 002b:00007953abffea90 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[   30.987222] RAX: ffffffffffffffda RBX: 00007953a0008620 RCX: 00007953bd8838db
[   30.987224] RDX: 000000002f404da0 RSI: 0000000040045612 RDI: 0000000000000013
[   30.987225] RBP: 000000002f404d90 R08: 00007953a000a9e0 R09: 0000000000000040
[   30.987225] R10: 00007953a000aa10 R11: 0000000000000246 R12: 0000000000000000
[   30.987226] R13: 00007953a0008638 R14: 0000000000000004 R15: 00007953a0008620
[   30.987228]  </TASK>
[   30.987263] Mem-Info:
[   30.987939] active_anon:3060 inactive_anon:1925 isolated_anon:0
[   30.987939]  active_file:5208 inactive_file:3901 isolated_file:0
[   30.987939]  unevictable:0 dirty:8 writeback:0
[   30.987939]  slab_reclaimable:2569 slab_unreclaimable:12482
[   30.987939]  mapped:5743 shmem:33 pagetables:1341
[   30.987939]  sec_pagetables:0 bounce:0
[   30.987939]  kernel_misc_reclaimable:0
[   30.987939]  free:2402 free_pcp:115 free_cma:0
[   30.988045] Node 0 active_anon:12240kB inactive_anon:7700kB active_file:20832kB inactive_file:15604kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:22972kB dirty:32kB writeback:0kB shmem:132kB shmem_thp:0kB shmem_pmdmapped:0kB anon_thp:0kB kernel_stack:3392kB pagetables:5364kB sec_pagetables:0kB all_unreclaimable? no Balloon:16384kB
[   30.988123] Node 0 DMA free:904kB boost:0kB min:132kB low:164kB high:196kB reserved_highatomic:0KB free_highatomic:0KB active_anon:1408kB inactive_anon:300kB active_file:368kB inactive_file:3664kB unevictable:0kB writepending:0kB zspages:0kB present:15992kB managed:15360kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[   30.988199] lowmem_reserve[]: 0 194 194 194 194
[   30.988227] Node 0 DMA32 free:8704kB boost:0kB min:1716kB low:2144kB high:2572kB reserved_highatomic:0KB free_highatomic:0KB active_anon:10832kB inactive_anon:7400kB active_file:20464kB inactive_file:11940kB unevictable:0kB writepending:32kB zspages:0kB present:274148kB managed:199276kB mlocked:0kB bounce:0kB free_pcp:456kB local_pcp:0kB free_cma:0kB
[   30.988305] lowmem_reserve[]: 0 0 0 0 0
[   30.988319] Node 0 DMA: 4*4kB (UM) 31*8kB (UM) 16*16kB (UM) 4*32kB (UM) 4*64kB (UM) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 904kB
[   30.988365] Node 0 DMA32: 604*4kB (UM) 524*8kB (UM) 108*16kB (UM) 10*32kB (UM) 1*64kB (U) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 8720kB
[   30.988422] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB
[   30.988448] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
[   30.988472] 11692 total pagecache pages
[   30.988483] 2568 pages in swap cache
[   30.988494] Free swap  = 891356kB
[   30.988505] Total swap = 1048572kB
[   30.988516] 72535 pages RAM
[   30.988524] 0 pages HighMem/MovableOnly
[   30.988535] 18876 pages reserved
[   30.988546] 0 pages cma reserved
[   30.988557] 0 pages hwpoisoned
[   30.988768] Memory allocations (profiling is currently turned on):
[   30.988789]     38.4 MiB     5505 mm/slub.c:3075 func:alloc_slab_page
[   30.988809]     33.0 MiB     8448 drivers/block/xen-blkfront.c:322 [xen_blkfront] func:fill_grant_buffer
[   30.988834]     31.9 MiB     7943 mm/readahead.c:189 func:ractl_alloc_folio
[   30.988852]     16.0 MiB     4096 drivers/xen/balloon.c:445 func:decrease_reservation
[   30.988873]     15.9 MiB     4064 drivers/media/common/videobuf2/videobuf2-vmalloc.c:47 [videobuf2_vmalloc] func:vb2_vmalloc_alloc
[   30.988905]     11.4 MiB     2924 mm/swap_state.c:439 func:__read_swap_cache_async
[   30.988926]     10.5 MiB     2904 mm/execmem.c:41 func:execmem_vmalloc
[   30.988944]     7.36 MiB      116 security/apparmor/policy_unpack.c:1361 func:compress_zstd
[   30.988966]     5.70 MiB      171 security/apparmor/policy_unpack.c:689 func:unpack_perms_table
[   30.989002]     5.57 MiB     1427 mm/memory.c:1191 func:folio_prealloc


-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

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Re: Linux 7.0-rc4: v4l2src0:src: page allocation failure - increased memory usage in 7.0?

[Harry Yoo]

On Fri, Mar 20, 2026 at 03:07:10PM +0100, Marek Marczykowski-Górecki wrote:
> On Fri, Mar 20, 2026 at 10:01:33AM +0900, Harry Yoo wrote:
> > On Thu, Mar 19, 2026 at 01:18:18AM +0100, Marek Marczykowski-Górecki wrote:
> > > Hello,
> > > 
> > > When testing 7.0-rc4 (and also got it with 7.0-rc1), I got page
> > > allocation failure in uvcvideo when using v4l2 camera in a VM. The setup
> > > is rather memory constrained - it's a HVM with just 300MB of memory
> > > running on Xen, with PCI passthrough of USB controllers (to which an USB
> > > camera is connected). But the very same setup works just fine with older
> > > kernel (last known good is 6.19.5, built with the same config).
> > 
> > Could you please share what /proc/meminfo looks like on v6.19, and
> > also enable memory allocation profiling feature [1] and see
> > what has changed between v6.19 and v7.0?
> > 
> > On v6.19, you should be able to see how much memory is allocated by
> > reading /proc/allocinfo.
> > 
> > On v7.0-rc4, warn_alloc() should let memory allocation profiling
> > print top users.
> > 
> > [1] https://docs.kernel.org/mm/allocation-profiling.html
> 
> Thanks, this got me some more info (below). That said, I think I spoke
> too soon about 6.19.5 - the page allocation failure happens there too,
> just without follow up crash, and v4l2 generally works afterwards (maybe
> few initial frames got lost? not sure) - so, I haven't noticed it
> before. So, it doesn't look like increased memory usage anymore.

Oh ok. So the allocation failure has already been there and the only new
part is handling of the failure.

> The message:
> 
> [   30.986973] v4l2src0:src: page allocation failure: order:5, mode:0xcc0(GFP_KERNEL), nodemask=(null),cpuset=/,mems_allowed=0
> [   30.987035] CPU: 1 UID: 1000 PID: 1256 Comm: v4l2src0:src Not tainted 6.19.5-1.qubes.42.fc41.x86_64 #1 PREEMPT(full) 
> [   30.987038] Hardware name: Xen HVM domU, BIOS 4.19.4 02/20/2026
> [   30.987039] Call Trace:
> [   30.987041]  <TASK>
> [   30.987044]  dump_stack_lvl+0x5d/0x80
> [   30.987049]  warn_alloc+0x162/0x190
> [   30.987052]  ? __alloc_pages_direct_compact+0x1bc/0x220
> [   30.987054]  __alloc_pages_slowpath.constprop.0+0x566/0x9b0
> [   30.987056]  ? kernfs_next_descendant_post+0x1b/0xe0
> [   30.987059]  __alloc_frozen_pages_noprof+0x31b/0x330
> [   30.987062]  __alloc_pages_noprof+0xe/0x20
> [   30.987063]  __dma_direct_alloc_pages.isra.0+0x1b2/0x3b0
> [   30.987066]  dma_direct_alloc_pages+0x3f/0x190
> [   30.987068]  alloc_single_sgt+0x12a/0x200
> [   30.987071]  dma_alloc_noncontiguous+0x49/0x150
> [   30.987074]  usb_alloc_noncoherent+0x45/0xa0
> [   30.987079]  uvc_alloc_urb_buffers.part.0+0x95/0x130 [uvcvideo]
> [   30.987092]  uvc_video_start_transfer+0x19d/0x4e0 [uvcvideo]
> [   30.987100]  uvc_video_start_streaming+0x9c/0x140 [uvcvideo]
> [   30.987107]  uvc_start_streaming_video+0x58/0x100 [uvcvideo]
> [   30.987116]  vb2_start_streaming+0x63/0x130 [videobuf2_common]
> [   30.987123]  vb2_core_streamon+0x98/0xf0 [videobuf2_common]
> [   30.987128]  ? vb2_ioctl_streamon+0x15/0x60 [videobuf2_v4l2]
> [   30.987133]  __video_do_ioctl+0x419/0x540 [videodev]
> [   30.987155]  video_usercopy+0x286/0x690 [videodev]
> [   30.987168]  ? __pfx___video_do_ioctl+0x10/0x10 [videodev]
> [   30.987181]  v4l2_ioctl+0x6b/0xa0 [videodev]
> [   30.987194]  __x64_sys_ioctl+0x96/0xe0
> [   30.987198]  do_syscall_64+0x84/0x6c0
> [   30.987201]  ? __handle_mm_fault+0x470/0x700
> [   30.987204]  ? count_memcg_events+0xdd/0x1a0
> [   30.987207]  ? handle_mm_fault+0x220/0x340
> [   30.987209]  ? do_user_addr_fault+0x2c3/0x7f0
> [   30.987212]  ? irqentry_exit+0x7a/0x510
> [   30.987214]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> [   30.987216] RIP: 0033:0x7953bd8838db
> [   30.987219] Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
> [   30.987220] RSP: 002b:00007953abffea90 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> [   30.987222] RAX: ffffffffffffffda RBX: 00007953a0008620 RCX: 00007953bd8838db
> [   30.987224] RDX: 000000002f404da0 RSI: 0000000040045612 RDI: 0000000000000013
> [   30.987225] RBP: 000000002f404d90 R08: 00007953a000a9e0 R09: 0000000000000040
> [   30.987225] R10: 00007953a000aa10 R11: 0000000000000246 R12: 0000000000000000
> [   30.987226] R13: 00007953a0008638 R14: 0000000000000004 R15: 00007953a0008620
> [   30.987228]  </TASK>
> [   30.987263] Mem-Info:
> [   30.987939] active_anon:3060 inactive_anon:1925 isolated_anon:0
> [   30.987939]  active_file:5208 inactive_file:3901 isolated_file:0
> [   30.987939]  unevictable:0 dirty:8 writeback:0
> [   30.987939]  slab_reclaimable:2569 slab_unreclaimable:12482
> [   30.987939]  mapped:5743 shmem:33 pagetables:1341
> [   30.987939]  sec_pagetables:0 bounce:0
> [   30.987939]  kernel_misc_reclaimable:0
> [   30.987939]  free:2402 free_pcp:115 free_cma:0

From 7.0.0:
    [  739.193907] Mem-Info:
    [  739.194897] active_anon:362 inactive_anon:3172 isolated_anon:0
    [  739.194897]  active_file:2498 inactive_file:11687 isolated_file:1
    [  739.194897]  unevictable:0 dirty:0 writeback:4
    [  739.194897]  slab_reclaimable:3707 slab_unreclaimable:10022
    [  739.194897]  mapped:4710 shmem:9 pagetables:1021
    [  739.194897]  sec_pagetables:0 bounce:0
    [  739.194897]  kernel_misc_reclaimable:0
    [  739.194897]  free:3452 free_pcp:1 free_cma:0

6.19.0->7.0.0:
{active,inactive,isolate}_anon: 4985 -> 3534 pages (- 5,804 KiB)
{active,inactive,isolated}_file: 9109 -> 13729 pages (+ 18,480 KiB)
anon+file: 14094 -> 17263 pages (+ 12,676 KiB)
slab_{reclaimable,unreclaimable}: 15051 -> 13729 pages (- 5,288 KiB)
free{,_pcp,_cma}: 2517 -> 3453 pages (+ 3,744 KiB)

Nothing surprising here.

-- 
Cheers,
Harry / Hyeonggon

> [   30.988045] Node 0 active_anon:12240kB inactive_anon:7700kB active_file:20832kB inactive_file:15604kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:22972kB dirty:32kB writeback:0kB shmem:132kB shmem_thp:0kB shmem_pmdmapped:0kB anon_thp:0kB kernel_stack:3392kB pagetables:5364kB sec_pagetables:0kB all_unreclaimable? no Balloon:16384kB
> [   30.988123] Node 0 DMA free:904kB boost:0kB min:132kB low:164kB high:196kB reserved_highatomic:0KB free_highatomic:0KB active_anon:1408kB inactive_anon:300kB active_file:368kB inactive_file:3664kB unevictable:0kB writepending:0kB zspages:0kB present:15992kB managed:15360kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> [   30.988199] lowmem_reserve[]: 0 194 194 194 194
> [   30.988227] Node 0 DMA32 free:8704kB boost:0kB min:1716kB low:2144kB high:2572kB reserved_highatomic:0KB free_highatomic:0KB active_anon:10832kB inactive_anon:7400kB active_file:20464kB inactive_file:11940kB unevictable:0kB writepending:32kB zspages:0kB present:274148kB managed:199276kB mlocked:0kB bounce:0kB free_pcp:456kB local_pcp:0kB free_cma:0kB
> [   30.988305] lowmem_reserve[]: 0 0 0 0 0
> [   30.988319] Node 0 DMA: 4*4kB (UM) 31*8kB (UM) 16*16kB (UM) 4*32kB (UM) 4*64kB (UM) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 904kB
> [   30.988365] Node 0 DMA32: 604*4kB (UM) 524*8kB (UM) 108*16kB (UM) 10*32kB (UM) 1*64kB (U) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 8720kB
> [   30.988422] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB
> [   30.988448] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
> [   30.988472] 11692 total pagecache pages
> [   30.988483] 2568 pages in swap cache
> [   30.988494] Free swap  = 891356kB
> [   30.988505] Total swap = 1048572kB
> [   30.988516] 72535 pages RAM
> [   30.988524] 0 pages HighMem/MovableOnly
> [   30.988535] 18876 pages reserved
> [   30.988546] 0 pages cma reserved
> [   30.988557] 0 pages hwpoisoned
> [   30.988768] Memory allocations (profiling is currently turned on):
> [   30.988789]     38.4 MiB     5505 mm/slub.c:3075 func:alloc_slab_page
> [   30.988809]     33.0 MiB     8448 drivers/block/xen-blkfront.c:322 [xen_blkfront] func:fill_grant_buffer
> [   30.988834]     31.9 MiB     7943 mm/readahead.c:189 func:ractl_alloc_folio
> [   30.988852]     16.0 MiB     4096 drivers/xen/balloon.c:445 func:decrease_reservation
> [   30.988873]     15.9 MiB     4064 drivers/media/common/videobuf2/videobuf2-vmalloc.c:47 [videobuf2_vmalloc] func:vb2_vmalloc_alloc
> [   30.988905]     11.4 MiB     2924 mm/swap_state.c:439 func:__read_swap_cache_async
> [   30.988926]     10.5 MiB     2904 mm/execmem.c:41 func:execmem_vmalloc
> [   30.988944]     7.36 MiB      116 security/apparmor/policy_unpack.c:1361 func:compress_zstd
> [   30.988966]     5.70 MiB      171 security/apparmor/policy_unpack.c:689 func:unpack_perms_table
> [   30.989002]     5.57 MiB     1427 mm/memory.c:1191 func:folio_prealloc