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authorOleg Nesterov <oleg@redhat.com>2012-08-08 17:11:42 +0200
committerOleg Nesterov <oleg@redhat.com>2012-08-28 18:21:18 +0200
commitf8ac4ec9c064b330dcc49e03c450fe74298c4622 (patch)
tree62d53120d0289719438d27de5f868c36e136ed28 /kernel/fork.c
parent78f7411668aa0b2006d331f6a288416dd91b8e5d (diff)
uprobes: Introduce MMF_HAS_UPROBES
Add the new MMF_HAS_UPROBES flag. It is set by install_breakpoint() and it is copied by dup_mmap(), uprobe_pre_sstep_notifier() checks it to avoid the slow path if the task was never probed. Perhaps it makes sense to check it in valid_vma(is_register => false) as well. This needs the new dup_mmap()->uprobe_dup_mmap() hook. We can't use uprobe_reset_state() or put MMF_HAS_UPROBES into MMF_INIT_MASK, we need oldmm->mmap_sem to avoid the race with uprobe_register() or mmap() from another thread. Currently we never clear this bit, it can be false-positive after uprobe_unregister() or uprobe_munmap() or if dup_mmap() hits the probed VM_DONTCOPY vma. But this is fine correctness-wise and has no effect unless the task hits the non-uprobe breakpoint. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/fork.c')
-rw-r--r--kernel/fork.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 912b6f6fe5b8..cbb5f9fcd3e8 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -353,6 +353,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
down_write(&oldmm->mmap_sem);
flush_cache_dup_mm(oldmm);
+ uprobe_dup_mmap(oldmm, mm);
/*
* Not linked in yet - no deadlock potential:
*/