[Qemu-devel] [PATCH] linux-user: Fix stale tbs after mmap

[Alexander Graf]

If we execute linux-user code that does the following:

  * A = mmap()
  * execute code in A
  * munmap(A)
  * B = mmap(), but mmap returns the same address as A
  * execute code in B

we end up executing a stale cached tb that contains translated code
from A, while we want new code from B.

This patch adds a TB flush for mmap'ed regions, before we return them,
avoiding the whole issue.

Reported-by: Peter Maydell <address@hidden>
Signed-off-by: Alexander Graf <address@hidden>
---
 linux-user/mmap.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 2620f88..390e940 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -587,6 +587,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int 
prot,
     page_dump(stdout);
     printf("\n");
 #endif
+    tb_invalidate_phys_page_range(start, start + len, 0);
     mmap_unlock();
     return start;
 fail:
@@ -768,6 +769,7 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong 
old_size,
         page_set_flags(old_addr, old_addr + old_size, 0);
         page_set_flags(new_addr, new_addr + new_size, prot | PAGE_VALID);
     }
+    tb_invalidate_phys_page_range(new_addr, new_addr + new_size, 0);
     mmap_unlock();
     return new_addr;
 }
-- 
1.6.0.2