diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2012-08-19 19:10:42 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-08-21 11:48:12 +0200 |
| commit | c7a3a88c938fbe3d70c2278e082b80eb830d1c58 (patch) | |
| tree | e25070dc5141c2614fbcfaae543de4237418a623 /mm/mmap.c | |
| parent | 9160338de92c0305329be5163a76f849806e83de (diff) | |
| download | linux-c7a3a88c938fbe3d70c2278e082b80eb830d1c58.tar.bz2 | |
uprobes: Fix mmap_region()'s mm->mm_rb corruption if uprobe_mmap() fails
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: <stable@vger.kernel.org> # v3.5
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>
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index e3e86914f11a..52e08fc9186d 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1356,9 +1356,8 @@ out: } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) make_pages_present(addr, addr + len); - if (file && uprobe_mmap(vma)) - /* matching probes but cannot insert */ - goto unmap_and_free_vma; + if (file) + uprobe_mmap(vma); return addr; |