[SCM] GNU Mach branch, master, updated. v1.8-864-g2981d798

[Samuel Thibault]

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       via  13b2f36d85756df7088be24acdcf847944b6b9ef (commit)
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- Log -----------------------------------------------------------------
commit 2981d798351958d2c153bd3cb3c00cc2ebc9f27c
Author: Damien Zammit <damien@zamaudio.com>
Date:   Thu Feb 22 08:24:39 2024 +0000

    kern/gsync: Use vm_map_lookup with keep_map_locked
    
    This prevents a deadlock in smp where a read lock on the map
    is taken in gsync and then the map is locked again inside
    vm_map_lookup() but another thread had a pre-existing write lock,
    therefore the second read lock blocks.
    
    This is fixed by removing the initial gsync read lock on the map
    but keeping the read lock held upon returning from vm_map_lookup().
    
    Co-Authored-By: Sergey Bugaev <bugaevc@gmail.com>
    Message-ID: <20240222082410.422869-4-damien@zamaudio.com>

commit 13b2f36d85756df7088be24acdcf847944b6b9ef
Author: Damien Zammit <damien@zamaudio.com>
Date:   Thu Feb 22 08:24:32 2024 +0000

    vm_map_lookup: Add parameter for keeping map locked
    
    This adds a parameter called keep_map_locked to vm_map_lookup()
    that allows the function to return with the map locked.
    
    This is to prepare for fixing a bug with gsync where the map
    is locked twice by mistake.
    
    Co-Authored-By: Sergey Bugaev <bugaevc@gmail.com>
    Message-ID: <20240222082410.422869-3-damien@zamaudio.com>

-----------------------------------------------------------------------

Summary of changes:
 i386/intel/read_fault.c |  4 ++--
 kern/gsync.c            | 19 ++++++-------------
 vm/vm_fault.c           |  4 ++--
 vm/vm_map.c             |  9 ++++++---
 vm/vm_map.h             |  2 +-
 5 files changed, 17 insertions(+), 21 deletions(-)


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