[to-be-updated] btrfs-avoid-live-lock-in-search_ioctl-on-hardware-with-sub-page-faults.patch removed from -mm tree

[to-be-updated] btrfs-avoid-live-lock-in-search_ioctl-on-hardware-with-sub-page-faults.patch removed from -mm tree

[akpm]

The patch titled
     Subject: btrfs: avoid live-lock in search_ioctl() on hardware with sub-page faults
has been removed from the -mm tree.  Its filename was
     btrfs-avoid-live-lock-in-search_ioctl-on-hardware-with-sub-page-faults.patch

This patch was dropped because an updated version will be merged

------------------------------------------------------
From: Catalin Marinas <catalin.marinas@arm.com>
Subject: btrfs: avoid live-lock in search_ioctl() on hardware with sub-page faults

Commit a48b73eca4ce ("btrfs: fix potential deadlock in the search ioctl")
addressed a lockdep warning by pre-faulting the user pages and attempting
the copy_to_user_nofault() in an infinite loop.  On architectures like
arm64 with MTE, an access may fault within a page at a location different
from what fault_in_writeable() probed.  Since the sk_offset is rewound to
the previous struct btrfs_ioctl_search_header boundary, there is no
guaranteed forward progress and search_ioctl() may live-lock.

Use fault_in_exact_writeable() instead which probes the entire user
buffer for faults at sub-page granularity.

Link: https://lkml.kernel.org/r/20211124192024.2408218-4-catalin.marinas@arm.com
Fixes: a48b73eca4ce ("btrfs: fix potential deadlock in the search ioctl") 
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: David Sterba <dsterba@suse.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/btrfs/ioctl.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/btrfs/ioctl.c~btrfs-avoid-live-lock-in-search_ioctl-on-hardware-with-sub-page-faults
+++ a/fs/btrfs/ioctl.c
@@ -2225,7 +2225,8 @@ static noinline int search_ioctl(struct
 
 	while (1) {
 		ret = -EFAULT;
-		if (fault_in_writeable(ubuf + sk_offset, *buf_size - sk_offset))
+		if (fault_in_exact_writeable(ubuf + sk_offset,
+					     *buf_size - sk_offset))
 			break;
 
 		ret = btrfs_search_forward(root, &key, path, sk->min_transid);
_

Patches currently in -mm which might be from catalin.marinas@arm.com are