[PULL,18/28] hw/block/pflash_cfi01: Don't decrement pfl->counter below 0

Commit Message

Philippe Mathieu-Daudé Aug. 6, 2024, 12:51 p.m. UTC

From: Peter Maydell <[e-mail]>

In pflash_write() Coverity points out that we can decrement the
unsigned pfl->counter below zero, which makes it wrap around.  In
fact this is harmless, because if pfl->counter is 0 at this point we
also increment pfl->wcycle to 3, and the wcycle == 3 handling doesn't
look at counter; the only way back into code which looks at the
counter value is via wcycle == 1, which will reinitialize the counter.
But it's arguably a little clearer to break early in the "counter ==
0" if(), to avoid the decrement-below-zero.

Resolves: Coverity CID 1547611
Signed-off-by: Peter Maydell <[e-mail]>
Reviewed-by: Kevin Wolf <[e-mail]>
Message-ID: <[e-mail]>
Signed-off-by: Philippe Mathieu-Daudé <[e-mail]>
---
 hw/block/pflash_cfi01.c | 1 +
 1 file changed, 1 insertion(+)

Patch

diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
index c8f1cf5a87..2f3d1dd509 100644
--- a/hw/block/pflash_cfi01.c
+++ b/hw/block/pflash_cfi01.c
@@ -614,6 +614,7 @@  static void pflash_write(PFlashCFI01 *pfl, hwaddr offset,
             if (!pfl->counter) {
                 trace_pflash_write(pfl->name, "block write finished");
                 pfl->wcycle++;
+                break;
             }
 
             pfl->counter--;