diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2012-08-19 19:10:42 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-09-14 09:59:55 -0700 |
| commit | a1ee34a43130fd31d7d0990695115a8e099b5ae6 (patch) | |
| tree | 171092385c57227cffe00b569a34e07106834fe0 /kernel | |
| parent | 2c43fd7058e779eeef7e3dad3a5a8066162cabac (diff) | |
uprobes: Fix mmap_region()'s mm->mm_rb corruption if uprobe_mmap() fails
commit c7a3a88c938fbe3d70c2278e082b80eb830d1c58 upstream.
This patch fixes:
https://bugzilla.redhat.com/show_bug.cgi?id=843640
If mmap_region()->uprobe_mmap() fails, unmap_and_free_vma path
does unmap_region() but does not remove the soon-to-be-freed vma
from rb tree. Actually there are more problems but this is how
William noticed this bug.
Perhaps we could do do_munmap() + return in this case, but in
fact it is simply wrong to abort if uprobe_mmap() fails. Until
at least we move the !UPROBE_COPY_INSN code from
install_breakpoint() to uprobe_register().
For example, uprobe_mmap()->install_breakpoint() can fail if the
probed insn is not supported (remember, uprobe_register()
succeeds if nobody mmaps inode/offset), mmap() should not fail
in this case.
dup_mmap()->uprobe_mmap() is wrong too by the same reason,
fork() can race with uprobe_register() and fail for no reason if
it wins the race and does install_breakpoint() first.
And, if nothing else, both mmap_region() and dup_mmap() return
success if uprobe_mmap() fails. Change them to ignore the error
code from uprobe_mmap().
Reported-and-tested-by: William Cohen <wcohen@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: William Cohen <wcohen@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20120819171042.GB26957@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/fork.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index f00e319d8376..f9d0499c2d27 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -459,8 +459,8 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) if (retval) goto out; - if (file && uprobe_mmap(tmp)) - goto out; + if (file) + uprobe_mmap(tmp); } /* a new mm has just been created */ arch_dup_mmap(oldmm, mm); |