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authorDavid Gibson <david@gibson.dropbear.id.au>2005-11-07 00:59:33 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-07 07:53:38 -0800
commit796f8d9b98fc92a5e9aaea8cf932957850332f51 (patch)
tree66e0a2bdf18e03c7dadba7c4c7b896533aa2e762
parentd55b5fdaf40846221d543937b786956e27837fda (diff)
[PATCH] FUTEX_WAKE_OP: enhanced error handling
The code for FUTEX_WAKE_OP calls an arch callback, futex_atomic_op_inuser(). That callback can return an error code, but currently the caller assumes any error is EFAULT, and will try various things to resolve the fault before eventually giving up with EFAULT (regardless of the original error code). This is not a theoretical case - arch callbacks currently return -ENOSYS if the opcode they are given is bogus. This patch alters the code to detect non-EFAULT errors and return them directly to the user. Of course, whether -ENOSYS is the correct return value for the bogus opcode case, or whether EINVAL would be more appropriate is another question. Signed-off-by: David Gibson <dwg@au1.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jamie Lokier <jamie@shareable.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--kernel/futex.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index 3b4d5ad44cc..aca8d10704f 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -365,6 +365,11 @@ retry:
if (bh1 != bh2)
spin_unlock(&bh2->lock);
+ if (unlikely(op_ret != -EFAULT)) {
+ ret = op_ret;
+ goto out;
+ }
+
/* futex_atomic_op_inuser needs to both read and write
* *(int __user *)uaddr2, but we can't modify it
* non-atomically. Therefore, if get_user below is not