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| author | David S. Miller <davem@davemloft.net> | 2020-07-25 17:49:04 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-07-25 17:49:04 -0700 |
| commit | a57066b1a01977a646145f4ce8dfb4538b08368a (patch) | |
| tree | 57c2b4fa2fc48e687a1820b9bf4ef4f4363be0f9 /mm/mremap.c | |
| parent | dfecd3e00cd32b2a6d1cfdb30b513dd42575ada3 (diff) | |
| parent | 04300d66f0a06d572d9f2ad6768c38cabde22179 (diff) | |
| download | linux-a57066b1a01977a646145f4ce8dfb4538b08368a.tar.bz2 | |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
The UDP reuseport conflict was a little bit tricky.
The net-next code, via bpf-next, extracted the reuseport handling
into a helper so that the BPF sk lookup code could invoke it.
At the same time, the logic for reuseport handling of unconnected
sockets changed via commit efc6b6f6c3113e8b203b9debfb72d81e0f3dcace
which changed the logic to carry on the reuseport result into the
rest of the lookup loop if we do not return immediately.
This requires moving the reuseport_has_conns() logic into the callers.
While we are here, get rid of inline directives as they do not belong
in foo.c files.
The other changes were cases of more straightforward overlapping
modifications.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'mm/mremap.c')
| -rw-r--r-- | mm/mremap.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index 5dd572d57ca9..6b153dc05fe4 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -206,9 +206,28 @@ static bool move_normal_pmd(struct vm_area_struct *vma, unsigned long old_addr, /* * The destination pmd shouldn't be established, free_pgtables() - * should have release it. + * should have released it. + * + * However, there's a case during execve() where we use mremap + * to move the initial stack, and in that case the target area + * may overlap the source area (always moving down). + * + * If everything is PMD-aligned, that works fine, as moving + * each pmd down will clear the source pmd. But if we first + * have a few 4kB-only pages that get moved down, and then + * hit the "now the rest is PMD-aligned, let's do everything + * one pmd at a time", we will still have the old (now empty + * of any 4kB pages, but still there) PMD in the page table + * tree. + * + * Warn on it once - because we really should try to figure + * out how to do this better - but then say "I won't move + * this pmd". + * + * One alternative might be to just unmap the target pmd at + * this point, and verify that it really is empty. We'll see. */ - if (WARN_ON(!pmd_none(*new_pmd))) + if (WARN_ON_ONCE(!pmd_none(*new_pmd))) return false; /* |