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| author | Dan Carpenter <dan.carpenter@oracle.com> | 2019-01-17 13:15:35 +0100 |
|---|---|---|
| committer | Matthew Wilcox <willy@infradead.org> | 2019-01-17 13:19:42 +0100 |
| commit | edcddd4c879af48ec922d680b2d56834c085683b (patch) | |
| tree | ef09fbfa2d681e0e1edb9005453d42d87d205d04 | |
| parent | XArray tests: Check mark 2 gets squashed (diff) | |
| download | linux-edcddd4c879af48ec922d680b2d56834c085683b.tar.xz linux-edcddd4c879af48ec922d680b2d56834c085683b.zip | |
XArray: Fix an arithmetic error in xa_is_err
There is a math problem here which leads to a lot of static checker
warnings for me:
net/sunrpc/clnt.c:451 rpc_new_client() error: (-4096) too low for ERR_PTR
Error values are from -1 to -4095 or from 0xffffffff to 0xfffff001 in
hexadecimal. (I am assuming a 32 bit system for simplicity). We are
using the lowest two bits to hold some internal XArray data so the
error is shifted two spaces to the left. 0xfffff001 << 2 is 0xffffc004.
And finally we want to check that BIT(1) is set so we add 2 which gives
us 0xffffc006.
In other words, we should be checking that "entry >= 0xffffc006", but
the check is actually testing if "entry >= 0xffffc002".
Fixes: 76b4e5299565 ("XArray: Permit storing 2-byte-aligned pointers")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
[Use xa_mk_internal() instead of changing the bracketing]
Signed-off-by: Matthew Wilcox <willy@infradead.org>
| -rw-r--r-- | include/linux/xarray.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 7da665f5cb20..5d9d318bcf7a 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -177,7 +177,7 @@ static inline bool xa_is_internal(const void *entry) static inline bool xa_is_err(const void *entry) { return unlikely(xa_is_internal(entry) && - (unsigned long)entry >= -((MAX_ERRNO << 2) + 2)); + entry >= xa_mk_internal(-MAX_ERRNO)); } /** |