Both register and unregister call build_map_info() in order
to create the list of mappings before installing or removing
breakpoints for every mm which maps file backed memory. As
such, there is no reason to hold the i_mmap_rwsem exclusively,
so share it and allow concurrent readers to build the mapping
data.
Signed-off-by: Davidlohr Bueso <dbu...@suse.de>
Acked-by: Srikar Dronamraju <sri...@linux.vnet.ibm.com>
Cc: Oleg Nesterov <o...@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shute...@intel.linux.com>
---
kernel/events/uprobes.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index e1bb60d..6158a64b 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -724,7 +724,7 @@ build_map_info(struct address_space *mapping, loff_t
offset, bool is_register)
int more = 0;
again:
- i_mmap_lock_write(mapping);
+ i_mmap_lock_read(mapping);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
if (!valid_vma(vma, is_register))
continue;
@@ -755,7 +755,7 @@ build_map_info(struct address_space *mapping, loff_t
offset, bool is_register)
info->mm = vma->vm_mm;
info->vaddr = offset_to_vaddr(vma, offset);
}
- i_mmap_unlock_write(mapping);
+ i_mmap_unlock_read(mapping);
if (!more)
goto out;
--
1.8.4.5
--
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