Bluetooth: hci_conn: Refactor hci_bind_bis() since it always succeeds

Commit Message

Kees Cook Jan. 28, 2023, 12:51 a.m. UTC

The compiler thinks "conn" might be NULL after a call to hci_bind_bis(),
which cannot happen. Avoid any confusion by just making it not return a
value since it cannot fail. Fixes the warnings seen with GCC 13:

In function 'arch_atomic_dec_and_test',
    inlined from 'atomic_dec_and_test' at ../include/linux/atomic/atomic-instrumented.h:576:9,
    inlined from 'hci_conn_drop' at ../include/net/bluetooth/hci_core.h:1391:6,
    inlined from 'hci_connect_bis' at ../net/bluetooth/hci_conn.c:2124:3:
../arch/x86/include/asm/rmwcc.h:37:9: warning: array subscript 0 is outside array bounds of 'atomic_t[0]' [-Warray-bounds=]
   37 |         asm volatile (fullop CC_SET(cc) \
      |         ^~~
...
In function 'hci_connect_bis':
cc1: note: source object is likely at address zero

Fixes: eca0ae4aea66 ("Bluetooth: Add initial implementation of BIS connections")
Cc: Luiz Augusto von Dentz <[e-mail]>
Cc: Marcel Holtmann <[e-mail]>
Cc: Johan Hedberg <[e-mail]>
Cc: "David S. Miller" <[e-mail]>
Cc: Eric Dumazet <[e-mail]>
Cc: Jakub Kicinski <[e-mail]>
Cc: Paolo Abeni <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Kees Cook <[e-mail]>
---
 net/bluetooth/hci_conn.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

Comments

[e-mail] Jan. 28, 2023, 1:15 a.m. UTC | #1

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Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=716493

---Test result---

Test Summary:
CheckPatch                    FAIL      1.23 seconds
GitLint                       FAIL      0.61 seconds
SubjectPrefix                 PASS      0.12 seconds
BuildKernel                   PASS      31.60 seconds
CheckAllWarning               PASS      34.13 seconds
CheckSparse                   PASS      38.76 seconds
CheckSmatch                   PASS      105.61 seconds
BuildKernel32                 PASS      30.23 seconds
TestRunnerSetup               PASS      435.80 seconds
TestRunner_l2cap-tester       PASS      16.61 seconds
TestRunner_iso-tester         PASS      17.48 seconds
TestRunner_bnep-tester        PASS      5.76 seconds
TestRunner_mgmt-tester        PASS      115.04 seconds
TestRunner_rfcomm-tester      PASS      9.17 seconds
TestRunner_sco-tester         PASS      8.47 seconds
TestRunner_ioctl-tester       PASS      10.05 seconds
TestRunner_mesh-tester        PASS      7.27 seconds
TestRunner_smp-tester         PASS      8.40 seconds
TestRunner_userchan-tester    PASS      6.03 seconds
IncrementalBuild              PASS      28.34 seconds

Details
##############################
Test: CheckPatch - FAIL
Desc: Run checkpatch.pl script
Output:
Bluetooth: hci_conn: Refactor hci_bind_bis() since it always succeeds
WARNING: Possible unwrapped commit description (prefer a maximum 75 chars per line)
#105: 
    inlined from 'atomic_dec_and_test' at ../include/linux/atomic/atomic-instrumented.h:576:9,

total: 0 errors, 1 warnings, 0 checks, 30 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

/github/workspace/src/src/13119595.patch has style problems, please review.

NOTE: Ignored message types: UNKNOWN_COMMIT_ID

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.


##############################
Test: GitLint - FAIL
Desc: Run gitlint
Output:
Bluetooth: hci_conn: Refactor hci_bind_bis() since it always succeeds

WARNING: I3 - ignore-body-lines: gitlint will be switching from using Python regex 'match' (match beginning) to 'search' (match anywhere) semantics. Please review your ignore-body-lines.regex option accordingly. To remove this warning, set general.regex-style-search=True. More details: https://jorisroovers.github.io/gitlint/configuration/#regex-style-search
8: B1 Line exceeds max length (94>80): "    inlined from 'atomic_dec_and_test' at ../include/linux/atomic/atomic-instrumented.h:576:9,"
11: B1 Line exceeds max length (123>80): "../arch/x86/include/asm/rmwcc.h:37:9: warning: array subscript 0 is outside array bounds of 'atomic_t[0]' [-Warray-bounds=]"


---
Regards,
Linux Bluetooth

Simon Horman Jan. 28, 2023, 1:44 p.m. UTC | #2

On Fri, Jan 27, 2023 at 04:51:54PM -0800, Kees Cook wrote:
> The compiler thinks "conn" might be NULL after a call to hci_bind_bis(),
> which cannot happen. Avoid any confusion by just making it not return a
> value since it cannot fail. Fixes the warnings seen with GCC 13:
> 
> In function 'arch_atomic_dec_and_test',
>     inlined from 'atomic_dec_and_test' at ../include/linux/atomic/atomic-instrumented.h:576:9,
>     inlined from 'hci_conn_drop' at ../include/net/bluetooth/hci_core.h:1391:6,
>     inlined from 'hci_connect_bis' at ../net/bluetooth/hci_conn.c:2124:3:
> ../arch/x86/include/asm/rmwcc.h:37:9: warning: array subscript 0 is outside array bounds of 'atomic_t[0]' [-Warray-bounds=]
>    37 |         asm volatile (fullop CC_SET(cc) \
>       |         ^~~
> ...
> In function 'hci_connect_bis':
> cc1: note: source object is likely at address zero
> 
> Fixes: eca0ae4aea66 ("Bluetooth: Add initial implementation of BIS connections")
...
> Signed-off-by: Kees Cook <[e-mail]>
> ---
>  net/bluetooth/hci_conn.c | 12 +++---------
>  1 file changed, 3 insertions(+), 9 deletions(-)

Is this really a 'fix' ?

In any case, the change looks good to me.

Reviewed-by: Simon Horman <[e-mail]>

[e-mail] Jan. 30, 2023, 9:30 p.m. UTC | #3

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <[e-mail]>:

On Fri, 27 Jan 2023 16:51:54 -0800 you wrote:
> The compiler thinks "conn" might be NULL after a call to hci_bind_bis(),
> which cannot happen. Avoid any confusion by just making it not return a
> value since it cannot fail. Fixes the warnings seen with GCC 13:
> 
> In function 'arch_atomic_dec_and_test',
>     inlined from 'atomic_dec_and_test' at ../include/linux/atomic/atomic-instrumented.h:576:9,
>     inlined from 'hci_conn_drop' at ../include/net/bluetooth/hci_core.h:1391:6,
>     inlined from 'hci_connect_bis' at ../net/bluetooth/hci_conn.c:2124:3:
> ../arch/x86/include/asm/rmwcc.h:37:9: warning: array subscript 0 is outside array bounds of 'atomic_t[0]' [-Warray-bounds=]
>    37 |         asm volatile (fullop CC_SET(cc) \
>       |         ^~~
> ...
> In function 'hci_connect_bis':
> cc1: note: source object is likely at address zero
> 
> [...]

Here is the summary with links:
  - Bluetooth: hci_conn: Refactor hci_bind_bis() since it always succeeds
    https://git.kernel.org/bluetooth/bluetooth-next/c/d57d873e6851

You are awesome, thank you!

Patch

diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index acf563fbdfd9..61a34801e61e 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -1981,16 +1981,14 @@  static void hci_iso_qos_setup(struct hci_dev *hdev, struct hci_conn *conn,
 		qos->latency = conn->le_conn_latency;
 }
 
-static struct hci_conn *hci_bind_bis(struct hci_conn *conn,
-				     struct bt_iso_qos *qos)
+static void hci_bind_bis(struct hci_conn *conn,
+			 struct bt_iso_qos *qos)
 {
 	/* Update LINK PHYs according to QoS preference */
 	conn->le_tx_phy = qos->out.phy;
 	conn->le_tx_phy = qos->out.phy;
 	conn->iso_qos = *qos;
 	conn->state = BT_BOUND;
-
-	return conn;
 }
 
 static int create_big_sync(struct hci_dev *hdev, void *data)
@@ -2119,11 +2117,7 @@  struct hci_conn *hci_connect_bis(struct hci_dev *hdev, bdaddr_t *dst,
 	if (IS_ERR(conn))
 		return conn;
 
-	conn = hci_bind_bis(conn, qos);
-	if (!conn) {
-		hci_conn_drop(conn);
-		return ERR_PTR(-ENOMEM);
-	}
+	hci_bind_bis(conn, qos);
 
 	/* Add Basic Announcement into Peridic Adv Data if BASE is set */
 	if (base_len && base) {