tmakin/ack-tegra
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ANDROID: 16K: Avoid mmap lock assertions for padding VMAs

Browse Source 
The padding VMA is never inserted into the VMA tree; therefore we
don't need to have the mmap lock in exclusive mode to modify it.

Test: v2/android-gki/ack_platform_integration_main_cf_arm64_boot_test
      on kernel_virt_debug_aarch64
Bug: 383389169
Bug: 346741763
Change-Id: I4ca3ed22dab45b6bb895cb41c5c6792344188b61
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
This commit is contained in:
Kalesh Singh
2024-06-17 15:38:32 -07:00
committed by Carlos Llamas
parent 4199eaf23e
commit 81734e02c6
1 changed files with 6 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
mm/pgsize_migration.c
View File

@@ -294,11 +294,14 @@ struct vm_area_struct *get_pad_vma(struct vm_area_struct *vma)
/* Adjust the start to begin at the start of the padding section */
pad->vm_start = VMA_PAD_START(pad);
/*
* The below modifications to vm_flags don't need mmap write lock,
* since, pad does not belong to the VMA tree.
*/
/* Make the pad vma PROT_NONE */
vm_flags_clear(pad, VM_READ|VM_WRITE|VM_EXEC);
__vm_flags_mod(pad, 0, VM_READ|VM_WRITE|VM_EXEC);
/* Remove padding bits */
vm_flags_clear(pad, VM_PAD_MASK);
__vm_flags_mod(pad, 0, VM_PAD_MASK);
return pad;
}