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| author | Jack Steiner <steiner@sgi.com> | 2009-06-17 16:28:33 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-18 13:04:04 -0700 |
| commit | 1926ee85a903d189c5702eed6531be321e33eb47 (patch) | |
| tree | 1ae951591d3be09b86479800e2a4f03f119f4d78 | |
| parent | b1b19fcfa417cf62447413d6e8b9b6598adf00b9 (diff) | |
| download | linux-stable-1926ee85a903d189c5702eed6531be321e33eb47.tar.gz linux-stable-1926ee85a903d189c5702eed6531be321e33eb47.tar.bz2 linux-stable-1926ee85a903d189c5702eed6531be321e33eb47.zip | |
gru: fix potential use-after-free when purging GRU tlbs
Fix potential SGI GRU bug that could cause a use-after-free. If one
thread in a task is flushing the GRU and another thread destroys the GRU
context, there is the potential to access a table after it has been freed.
Copy the gms pointer to a local variable before unlocking the gts table.
Note that no refcnt is needed for the gms - the reference is held
indirectly by the task's mm_struct.
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/misc/sgi-gru/grufault.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c index 1ad360cd3183..679e01778286 100644 --- a/drivers/misc/sgi-gru/grufault.c +++ b/drivers/misc/sgi-gru/grufault.c @@ -702,6 +702,7 @@ int gru_user_flush_tlb(unsigned long arg) { struct gru_thread_state *gts; struct gru_flush_tlb_req req; + struct gru_mm_struct *gms; STAT(user_flush_tlb); if (copy_from_user(&req, (void __user *)arg, sizeof(req))) @@ -714,8 +715,9 @@ int gru_user_flush_tlb(unsigned long arg) if (!gts) return -EINVAL; - gru_flush_tlb_range(gts->ts_gms, req.vaddr, req.len); + gms = gts->ts_gms; gru_unlock_gts(gts); + gru_flush_tlb_range(gms, req.vaddr, req.len); return 0; } |