lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <1414697657-1678-6-git-send-email-dave@stgolabs.net>
Date:	Thu, 30 Oct 2014 12:34:12 -0700
From:	Davidlohr Bueso <dave@...olabs.net>
To:	akpm@...ux-foundation.org
Cc:	hughd@...gle.com, riel@...hat.com, mgorman@...e.de,
	peterz@...radead.org, mingo@...nel.org,
	linux-kernel@...r.kernel.org, dbueso@...e.de, linux-mm@...ck.org,
	Davidlohr Bueso <dave@...olabs.net>,
	Oleg Nesterov <oleg@...hat.com>
Subject: [PATCH 05/10] uprobes: share the i_mmap_rwsem

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 <dbueso@...e.de>
Acked-by: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@...hat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@...el.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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ