** Changed in: linux-oem-6.11 (Ubuntu Noble)
Status: In Progress => Fix Committed
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https://bugs.launchpad.net/bugs/2086668
Title:
NVIDIA WANR_ON call trace right after power on or resumed on 6.11
kernel
Status in HWE Next:
New
Status in linux-oem-6.11 package in Ubuntu:
Invalid
Status in linux-oem-6.11 source package in Noble:
Fix Committed
Bug description:
[Impact]
Shows follow_pte() warning with nvidia dirver + 6.11 kernel.
Aug 09 09:20:42 ubuntu-202407-34200 kernel: WARNING: CPU: 0 PID: 2918
at include/linux/rwsem.h:80 follow_pte+0x220/0x230
[Fix]
This occurs during suspend when a function from the NVIDIA
'nv_revoke_gpu_mappings_locked()' calls the kernel function
'unmap_mapping_range()', which eventually ends up calling 'follow_pte()'. The
function 'follow_pte()' calls an assertion 'mmap_assert_locked' to check if the
'mmap_lock' has been taken.
This assertion fails, and we see a warning call trace (no functional issue,
just some output in dmesg). All of this happens in kernel versions v6.10
through v6.11.
This is a kernel bug, not an NVIDIA driver bug, and has also been discussed
here in the kernel mailing list :
https://lore.kernel.org/linux-mm/20240712080414.ga47...@google.com/T/#u
There is a series of patches to address this issue and replace the
follow_pte()
https://lore.kernel.org/linux-mm/20240809160909.1023470-1-pet...@redhat.com/
We try to cherry pick the new functions and at the same time preserve the
follow_pte() for compatiblity with the old drivers.
b1b46751671b mm: fix follow_pfnmap API lockdep assert
75182022a043 mm/x86: support large pfn mappings
cbea8536d933 mm/x86/pat: use the new follow_pfnmap API
6da8e9634bb7 mm: new follow_pfnmap API
6857be5fecae mm: introduce ARCH_SUPPORTS_HUGE_PFNMAP and special bits to
pmd/pud
[Test]
1. Boot up the machine with 6.11 kernel + nvidia driver
2. Do suspend/resume and check dmesg
3. There should be no nvidia call trace
[Where problems could occur]
Only this patch change the code that uses follow_pfnmap() to replace
follow_pfn()
cbea8536d933 ("mm/x86/pat: use the new follow_pfnmap API")
The changes are 1x1 mappingable and should do the identical things.
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