Bug#1029968: bttv/v4l: WARNING: CPU: 6 PID: 6164 at mm/vmalloc.c:487 __vmap_pages_range_noflush+0x3e0/0x4d0

Package: src:linux Version: 6.1.4-1 Severity: normal Dear Maintainer, *** Reporter, please consider answering these questions, where appropriate *** * What led up to the situation? This was triggered when trying to capture video via a bt878 card using the

Bug#1029968: bisecting we go...

t's changed from a BUG to a WARN but back in 5.15 it just worked. Dave -- -Open up your eyes, open up your mind, open up your code --- / Dr. David Alan Gilbert| Running GNU/Linux | Happy \ \dave @ treblig.org | | In

Bug#1029968: Acknowledgement (bttv/v4l: WARNING: CPU: 6 PID: 6164 at mm/vmalloc.c:487 __vmap_pages_range_noflush+0x3e0/0x4d0)

eyes, open up your mind, open up your code --- / Dr. David Alan Gilbert| Running GNU/Linux | Happy \ \dave @ treblig.org | | In Hex / \ _|_ http://www.treblig.org |___/

Bug#1029968: Acknowledgement (bttv/v4l: WARNING: CPU: 6 PID: 6164 at mm/vmalloc.c:487 __vmap_pages_range_noflush+0x3e0/0x4d0)

I built upstream kernels 5.18.0 and 6.1.0 and both of them work for me. Which makes life much more painful to find. -- -Open up your eyes, open up your mind, open up your code --- / Dr. David Alan Gilbert| Running GNU/Linux | Happy \ \dave @ treblig.org

Bug#1029968: Acknowledgement (bttv/v4l: WARNING: CPU: 6 PID: 6164 at mm/vmalloc.c:487 __vmap_pages_range_noflush+0x3e0/0x4d0)

This is IOMMU related. Upstream 6.1 and 5.18 *do* exhibit the bug, but only with intel_iommu=on where as Debian seems to default it to on. -- -Open up your eyes, open up your mind, open up your code --- / Dr. David Alan Gilbert| Running GNU/Linux | Happy

Bug#1029968: Acknowledgement (bttv/v4l: WARNING: CPU: 6 PID: 6164 at mm/vmalloc.c:487 __vmap_pages_range_noflush+0x3e0/0x4d0)

Upstream 5.17 works Upstream 5.18 fails (with intel_iommu=on) Let the bisect begin. -- -Open up your eyes, open up your mind, open up your code --- / Dr. David Alan Gilbert| Running GNU/Linux | Happy \ \dave @ treblig.org

Bug#1029968: Info received (Bug#1029968: Info received (Bug#1029968: Info received (Bug#1029968: Acknowledgement (bttv/v4l: WARNING: CPU: 6 PID: 6164 at mm/vmalloc.c:487 __vmap_pages_range_noflush+0x3

I sent this upstream report: https://lore.kernel.org/linux-iommu/Y9qSwkLxeMpffZK%2F@gallifrey/T/#u -- -Open up your eyes, open up your mind, open up your code --- / Dr. David Alan Gilbert| Running GNU/Linux | Happy \ \dave @ treblig.org

Bug#1029968: Info received (Bug#1029968: Info received (Bug#1029968: Info received (Bug#1029968: Acknowledgement (bttv/v4l: WARNING: CPU: 6 PID: 6164 at mm/vmalloc.c:487 __vmap_pages_range_noflush+0x3

iommu 2) some v4l tools can use an mmap interface rather than the read(2) interface; that seems to be OK. Dave -- -Open up your eyes, open up your mind, open up your code --- / Dr. David Alan Gilbert| Running GNU/Linux | Happy \ \dave @ treblig.org

Bug#1029968: Acknowledgement (bttv/v4l: WARNING: CPU: 6 PID: 6164 at mm/vmalloc.c:487 __vmap_pages_range_noflush+0x3e0/0x4d0)

U related and device related. -- -Open up your eyes, open up your mind, open up your code --- / Dr. David Alan Gilbert| Running GNU/Linux | Happy \ \dave @ treblig.org | | In Hex / \ _|_ http://www.treblig.org |___/

Bug#1029968: Info received (Bug#1029968: Acknowledgement (bttv/v4l: WARNING: CPU: 6 PID: 6164 at mm/vmalloc.c:487 __vmap_pages_range_noflush+0x3e0/0x4d0))

050033 [ 78.988346] CR2: bd7fc110 CR3: 00022ce02000 CR4: 06e0 -- -Open up your eyes, open up your mind, open up your code --- / Dr. David Alan Gilbert| Running GNU/Linux | Happy \ \dave @ treblig.org | |

Bug#1029968: Acknowledgement (bttv/v4l: WARNING: CPU: 6 PID: 6164 at mm/vmalloc.c:487 __vmap_pages_range_noflush+0x3e0/0x4d0)

open up your code --- / Dr. David Alan Gilbert| Running GNU/Linux | Happy \ \dave @ treblig.org | | In Hex / \ _|_ http://www.treblig.org |___/

Bug#1029968: Info received (Bug#1029968: Info received (Bug#1029968: Acknowledgement (bttv/v4l: WARNING: CPU: 6 PID: 6164 at mm/vmalloc.c:487 __vmap_pages_range_noflush+0x3e0/0x4d0)))

Confirmed still happens on upstream 6.2.0-rc6 -- -Open up your eyes, open up your mind, open up your code --- / Dr. David Alan Gilbert| Running GNU/Linux | Happy \ \dave @ treblig.org | | In Hex

Bug#1029968: And some patches

As well as the fixes in 6.6, we also need this patchup series here: https://lore.kernel.org/linux-media/ZWibhE350L3BTRK8@gallifrey/T/#t These seem to make it pretty nicely. -- -Open up your eyes, open up your mind, open up your code --- / Dr. David Alan Gilbert| Running

Bug#1029968: fixed in 6.6

-- -Open up your eyes, open up your mind, open up your code --- / Dr. David Alan Gilbert| Running GNU/Linux | Happy \ \dave @ treblig.org | | In Hex / \ _|_ http://www.treblig.org |___/