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| author | Gustavo A. R. Silva <gustavoars@kernel.org> | 2020-05-07 22:21:47 +0300 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2020-05-12 05:26:32 +0300 |
| commit | 00b42b70ae521e6ccc86ed403e2d101616689bdc (patch) | |
| tree | 3f3ff3ed8080a312322d9c414fcbb47d13f548aa /include/scsi | |
| parent | f9491ed56e3a73aaa27accf4600671611dcf18bd (diff) | |
| download | linux-00b42b70ae521e6ccc86ed403e2d101616689bdc.tar.xz | |
scsi: libsas: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare variable-length
types such as these ones is a flexible array member[1][2], introduced in
C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by this
change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in which
the sizeof operator is being incorrectly/erroneously applied to zero-length
arrays and the result is zero. Such instances may be hiding some bugs. So,
this work (flexible-array member conversions) will also help to get
completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Link: https://lore.kernel.org/r/20200507192147.GA16206@embeddedor
Reviewed-by: John Garry <john.garry@huawei.com>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'include/scsi')
| -rw-r--r-- | include/scsi/sas.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/include/scsi/sas.h b/include/scsi/sas.h index a5d8ae49198c..4726c1bbec65 100644 --- a/include/scsi/sas.h +++ b/include/scsi/sas.h @@ -324,7 +324,7 @@ struct ssp_response_iu { __be32 response_data_len; u8 resp_data[0]; - u8 sense_data[0]; + u8 sense_data[]; } __attribute__ ((packed)); struct ssp_command_iu { @@ -346,7 +346,7 @@ struct ssp_command_iu { u8 add_cdb_len:6; u8 cdb[16]; - u8 add_cdb[0]; + u8 add_cdb[]; } __attribute__ ((packed)); struct xfer_rdy_iu { @@ -555,7 +555,7 @@ struct ssp_response_iu { __be32 response_data_len; u8 resp_data[0]; - u8 sense_data[0]; + u8 sense_data[]; } __attribute__ ((packed)); struct ssp_command_iu { @@ -577,7 +577,7 @@ struct ssp_command_iu { u8 _r_c:2; u8 cdb[16]; - u8 add_cdb[0]; + u8 add_cdb[]; } __attribute__ ((packed)); struct xfer_rdy_iu { |