[v2,next] Bluetooth: L2CAP: Avoid -Wflex-array-member-not-at-end warnings

Commit Message

Gustavo A. R. Silva March 27, 2024, 4:23 p.m. UTC

-Wflex-array-member-not-at-end is coming in GCC-14, and we are getting
ready to enable it globally.

There are currently a couple of objects (`req` and `rsp`), in a couple
of structures, that contain flexible structures (`struct l2cap_ecred_conn_req`
and `struct l2cap_ecred_conn_rsp`), for example:

struct l2cap_ecred_rsp_data {
        struct {
                struct l2cap_ecred_conn_rsp rsp;
                __le16 scid[L2CAP_ECRED_MAX_CID];
        } __packed pdu;
        int count;
};

in the struct above, `struct l2cap_ecred_conn_rsp` is a flexible
structure:

struct l2cap_ecred_conn_rsp {
        __le16 mtu;
        __le16 mps;
        __le16 credits;
        __le16 result;
        __le16 dcid[];
};

So, in order to avoid ending up with a flexible-array member in the
middle of another structure, we use the `struct_group_tagged()` (and
`__struct_group()` when the flexible structure is `__packed`) helper
to separate the flexible array from the rest of the members in the
flexible structure:

struct l2cap_ecred_conn_rsp {
        struct_group_tagged(l2cap_ecred_conn_rsp_hdr, hdr,

	... the rest of members

        );
        __le16 dcid[];
};

With the change described above, we now declare objects of the type of
the tagged struct, in this example `struct l2cap_ecred_conn_rsp_hdr`,
without embedding flexible arrays in the middle of other structures:

struct l2cap_ecred_rsp_data {
        struct {
                struct l2cap_ecred_conn_rsp_hdr rsp;
                __le16 scid[L2CAP_ECRED_MAX_CID];
        } __packed pdu;
        int count;
};

Also, when the flexible-array member needs to be accessed, we use
`container_of()` to retrieve a pointer to the flexible structure.

We also use the `DEFINE_RAW_FLEX()` helper for a couple of on-stack
definitions of a flexible structure where the size of the flexible-array
member is known at compile-time.

So, with these changes, fix the following warnings:
net/bluetooth/l2cap_core.c:1260:45: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
net/bluetooth/l2cap_core.c:3740:45: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
net/bluetooth/l2cap_core.c:4999:45: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
net/bluetooth/l2cap_core.c:7116:47: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Link: https://github.com/KSPP/linux/issues/202
Signed-off-by: Gustavo A. R. Silva <[e-mail]>
---
Changes in v2:
 - Add a couple of code comments.

v1:
 - Link: https://lore.kernel.org/linux-hardening/ZgMpynzZ8FltPCi3@neat/

Hi!

I wonder if `struct l2cap_ecred_conn_rsp` should also be `__packed`.

Thanks
 - Gustavo

 include/net/bluetooth/l2cap.h | 22 +++++++++++------
 net/bluetooth/l2cap_core.c    | 46 ++++++++++++++++-------------------
 2 files changed, 35 insertions(+), 33 deletions(-)

Comments

[e-mail] March 27, 2024, 4:52 p.m. UTC | #1

This is automated email and please do not reply to this email!

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=838965

---Test result---

Test Summary:
CheckPatch                    FAIL      1.10 seconds
GitLint                       FAIL      0.57 seconds
SubjectPrefix                 PASS      0.13 seconds
BuildKernel                   FAIL      24.63 seconds
CheckAllWarning               FAIL      26.66 seconds
CheckSparse                   FAIL      31.03 seconds
CheckSmatch                   FAIL      35.24 seconds
BuildKernel32                 FAIL      23.48 seconds
TestRunnerSetup               FAIL      499.56 seconds
TestRunner_l2cap-tester       FAIL      0.15 seconds
TestRunner_iso-tester         FAIL      0.15 seconds
TestRunner_bnep-tester        FAIL      0.15 seconds
TestRunner_mgmt-tester        FAIL      0.15 seconds
TestRunner_rfcomm-tester      FAIL      0.15 seconds
TestRunner_sco-tester         FAIL      0.15 seconds
TestRunner_ioctl-tester       FAIL      0.15 seconds
TestRunner_mesh-tester        FAIL      0.15 seconds
TestRunner_smp-tester         FAIL      0.15 seconds
TestRunner_userchan-tester    FAIL      0.15 seconds
IncrementalBuild              FAIL      22.41 seconds

Details
##############################
Test: CheckPatch - FAIL
Desc: Run checkpatch.pl script
Output:
[v2,next] Bluetooth: L2CAP: Avoid -Wflex-array-member-not-at-end warnings
WARNING: Prefer a maximum 75 chars per line (possible unwrapped commit description?)
#69: 
of structures, that contain flexible structures (`struct l2cap_ecred_conn_req`

total: 0 errors, 1 warnings, 0 checks, 152 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/13607060.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:
[v2,next] Bluetooth: L2CAP: Avoid -Wflex-array-member-not-at-end warnings

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
38: B3 Line contains hard tab characters (\t): "	... the rest of members"
64: B1 Line exceeds max length (161>80): "net/bluetooth/l2cap_core.c:1260:45: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]"
65: B1 Line exceeds max length (161>80): "net/bluetooth/l2cap_core.c:3740:45: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]"
66: B1 Line exceeds max length (161>80): "net/bluetooth/l2cap_core.c:4999:45: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]"
67: B1 Line exceeds max length (161>80): "net/bluetooth/l2cap_core.c:7116:47: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]"
##############################
Test: BuildKernel - FAIL
Desc: Build Kernel for Bluetooth
Output:

net/bluetooth/l2cap_core.c: In function ‘l2cap_ecred_conn_req’:
net/bluetooth/l2cap_core.c:5000:2: error: implicit declaration of function ‘DEFINE_RAW_FLEX’; did you mean ‘DEFINE_FLEX’? [-Werror=implicit-function-declaration]
 5000 |  DEFINE_RAW_FLEX(struct l2cap_ecred_conn_rsp, pdu, dcid, L2CAP_ECRED_MAX_CID);
      |  ^~~~~~~~~~~~~~~
      |  DEFINE_FLEX
net/bluetooth/l2cap_core.c:5000:18: error: expected expression before ‘struct’
 5000 |  DEFINE_RAW_FLEX(struct l2cap_ecred_conn_rsp, pdu, dcid, L2CAP_ECRED_MAX_CID);
      |                  ^~~~~~
net/bluetooth/l2cap_core.c:5048:9: error: ‘pdu’ undeclared (first use in this function)
 5048 |  memset(pdu, 0, sizeof(*pdu));
      |         ^~~
net/bluetooth/l2cap_core.c:5048:9: note: each undeclared identifier is reported only once for each function it appears in
net/bluetooth/l2cap_core.c: In function ‘l2cap_ecred_reconfigure’:
net/bluetooth/l2cap_core.c:7114:18: error: expected expression before ‘struct’
 7114 |  DEFINE_RAW_FLEX(struct l2cap_ecred_reconf_req, pdu, scid, 1);
      |                  ^~~~~~
net/bluetooth/l2cap_core.c:7116:2: error: ‘pdu’ undeclared (first use in this function)
 7116 |  pdu->mtu = cpu_to_le16(chan->imtu);
      |  ^~~
cc1: some warnings being treated as errors
make[4]: *** [scripts/Makefile.build:244: net/bluetooth/l2cap_core.o] Error 1
make[3]: *** [scripts/Makefile.build:485: net/bluetooth] Error 2
make[2]: *** [scripts/Makefile.build:485: net] Error 2
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [/github/workspace/src/src/Makefile:1919: .] Error 2
make: *** [Makefile:240: __sub-make] Error 2
##############################
Test: CheckAllWarning - FAIL
Desc: Run linux kernel with all warning enabled
Output:

net/bluetooth/l2cap_core.c: In function ‘l2cap_ecred_conn_req’:
net/bluetooth/l2cap_core.c:5000:2: error: implicit declaration of function ‘DEFINE_RAW_FLEX’; did you mean ‘DEFINE_FLEX’? [-Werror=implicit-function-declaration]
 5000 |  DEFINE_RAW_FLEX(struct l2cap_ecred_conn_rsp, pdu, dcid, L2CAP_ECRED_MAX_CID);
      |  ^~~~~~~~~~~~~~~
      |  DEFINE_FLEX
net/bluetooth/l2cap_core.c:5000:18: error: expected expression before ‘struct’
 5000 |  DEFINE_RAW_FLEX(struct l2cap_ecred_conn_rsp, pdu, dcid, L2CAP_ECRED_MAX_CID);
      |                  ^~~~~~
net/bluetooth/l2cap_core.c:5048:9: error: ‘pdu’ undeclared (first use in this function)
 5048 |  memset(pdu, 0, sizeof(*pdu));
      |         ^~~
net/bluetooth/l2cap_core.c:5048:9: note: each undeclared identifier is reported only once for each function it appears in
net/bluetooth/l2cap_core.c: In function ‘l2cap_ecred_reconfigure’:
net/bluetooth/l2cap_core.c:7114:18: error: expected expression before ‘struct’
 7114 |  DEFINE_RAW_FLEX(struct l2cap_ecred_reconf_req, pdu, scid, 1);
      |                  ^~~~~~
net/bluetooth/l2cap_core.c:7116:2: error: ‘pdu’ undeclared (first use in this function)
 7116 |  pdu->mtu = cpu_to_le16(chan->imtu);
      |  ^~~
cc1: some warnings being treated as errors
make[4]: *** [scripts/Makefile.build:244: net/bluetooth/l2cap_core.o] Error 1
make[3]: *** [scripts/Makefile.build:485: net/bluetooth] Error 2
make[2]: *** [scripts/Makefile.build:485: net] Error 2
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [/github/workspace/src/src/Makefile:1919: .] Error 2
make: *** [Makefile:240: __sub-make] Error 2
##############################
Test: CheckSparse - FAIL
Desc: Run sparse tool with linux kernel
Output:

net/bluetooth/af_bluetooth.c:223:25: warning: context imbalance in 'bt_accept_enqueue' - different lock contexts for basic block
drivers/bluetooth/hci_ag6xx.c:257:24: warning: restricted __le32 degrades to integer
drivers/bluetooth/hci_mrvl.c:170:23: warning: restricted __le16 degrades to integer
drivers/bluetooth/hci_mrvl.c:203:23: warning: restricted __le16 degrades to integer
net/bluetooth/hci_event.c: note: in included file (through include/net/bluetooth/hci_core.h):
./include/net/bluetooth/hci.h:2691:47: warning: array of flexible structures
./include/net/bluetooth/hci.h:2777:43: warning: array of flexible structures
net/bluetooth/l2cap_core.c: In function ‘l2cap_ecred_conn_req’:
net/bluetooth/l2cap_core.c:5000:2: error: implicit declaration of function ‘DEFINE_RAW_FLEX’; did you mean ‘DEFINE_FLEX’? [-Werror=implicit-function-declaration]
 5000 |  DEFINE_RAW_FLEX(struct l2cap_ecred_conn_rsp, pdu, dcid, L2CAP_ECRED_MAX_CID);
      |  ^~~~~~~~~~~~~~~
      |  DEFINE_FLEX
net/bluetooth/l2cap_core.c:5000:18: error: expected expression before ‘struct’
 5000 |  DEFINE_RAW_FLEX(struct l2cap_ecred_conn_rsp, pdu, dcid, L2CAP_ECRED_MAX_CID);
      |                  ^~~~~~
net/bluetooth/l2cap_core.c:5048:9: error: ‘pdu’ undeclared (first use in this function)
 5048 |  memset(pdu, 0, sizeof(*pdu));
      |         ^~~
net/bluetooth/l2cap_core.c:5048:9: note: each undeclared identifier is reported only once for each function it appears in
net/bluetooth/l2cap_core.c: In function ‘l2cap_ecred_reconfigure’:
net/bluetooth/l2cap_core.c:7114:18: error: expected expression before ‘struct’
 7114 |  DEFINE_RAW_FLEX(struct l2cap_ecred_reconf_req, pdu, scid, 1);
      |                  ^~~~~~
net/bluetooth/l2cap_core.c:7116:2: error: ‘pdu’ undeclared (first use in this function)
 7116 |  pdu->mtu = cpu_to_le16(chan->imtu);
      |  ^~~
cc1: some warnings being treated as errors
make[4]: *** [scripts/Makefile.build:244: net/bluetooth/l2cap_core.o] Error 1
make[3]: *** [scripts/Makefile.build:485: net/bluetooth] Error 2
make[2]: *** [scripts/Makefile.build:485: net] Error 2
make[2]: *** Waiting for unfinished jobs....
drivers/bluetooth/hci_nokia.c:284:23: warning: incorrect type in assignment (different base types)
drivers/bluetooth/hci_nokia.c:284:23:    expected unsigned short [usertype] baud
drivers/bluetooth/hci_nokia.c:284:23:    got restricted __le16 [usertype]
drivers/bluetooth/hci_nokia.c:287:26: warning: incorrect type in assignment (different base types)
drivers/bluetooth/hci_nokia.c:287:26:    expected unsigned short [usertype] sys_clk
drivers/bluetooth/hci_nokia.c:287:26:    got restricted __le16 [usertype]
make[1]: *** [/github/workspace/src/src/Makefile:1919: .] Error 2
make: *** [Makefile:240: __sub-make] Error 2
##############################
Test: CheckSmatch - FAIL
Desc: Run smatch tool with source
Output:

Segmentation fault (core dumped)
make[4]: *** [scripts/Makefile.build:244: net/bluetooth/hci_core.o] Error 139
make[4]: *** Deleting file 'net/bluetooth/hci_core.o'
make[3]: *** [scripts/Makefile.build:485: net/bluetooth] Error 2
make[2]: *** [scripts/Makefile.build:485: net] Error 2
make[2]: *** Waiting for unfinished jobs....
Segmentation fault (core dumped)
make[4]: *** [scripts/Makefile.build:244: drivers/bluetooth/bcm203x.o] Error 139
make[4]: *** Deleting file 'drivers/bluetooth/bcm203x.o'
make[4]: *** Waiting for unfinished jobs....
make[3]: *** [scripts/Makefile.build:485: drivers/bluetooth] Error 2
make[2]: *** [scripts/Makefile.build:485: drivers] Error 2
make[1]: *** [/github/workspace/src/src/Makefile:1919: .] Error 2
make: *** [Makefile:240: __sub-make] Error 2
##############################
Test: BuildKernel32 - FAIL
Desc: Build 32bit Kernel for Bluetooth
Output:

net/bluetooth/l2cap_core.c: In function ‘l2cap_ecred_conn_req’:
net/bluetooth/l2cap_core.c:5000:2: error: implicit declaration of function ‘DEFINE_RAW_FLEX’; did you mean ‘DEFINE_FLEX’? [-Werror=implicit-function-declaration]
 5000 |  DEFINE_RAW_FLEX(struct l2cap_ecred_conn_rsp, pdu, dcid, L2CAP_ECRED_MAX_CID);
      |  ^~~~~~~~~~~~~~~
      |  DEFINE_FLEX
net/bluetooth/l2cap_core.c:5000:18: error: expected expression before ‘struct’
 5000 |  DEFINE_RAW_FLEX(struct l2cap_ecred_conn_rsp, pdu, dcid, L2CAP_ECRED_MAX_CID);
      |                  ^~~~~~
In file included from ./arch/x86/include/asm/string.h:3,
                 from ./arch/x86/include/asm/cpuid.h:9,
                 from ./arch/x86/include/asm/processor.h:19,
                 from ./arch/x86/include/asm/timex.h:5,
                 from ./include/linux/timex.h:67,
                 from ./include/linux/time32.h:13,
                 from ./include/linux/time.h:60,
                 from ./include/linux/stat.h:19,
                 from ./include/linux/module.h:13,
                 from net/bluetooth/l2cap_core.c:31:
net/bluetooth/l2cap_core.c:5048:9: error: ‘pdu’ undeclared (first use in this function)
 5048 |  memset(pdu, 0, sizeof(*pdu));
      |         ^~~
./arch/x86/include/asm/string_32.h:195:46: note: in definition of macro ‘memset’
  195 | #define memset(s, c, count) __builtin_memset(s, c, count)
      |                                              ^
net/bluetooth/l2cap_core.c:5048:9: note: each undeclared identifier is reported only once for each function it appears in
 5048 |  memset(pdu, 0, sizeof(*pdu));
      |         ^~~
./arch/x86/include/asm/string_32.h:195:46: note: in definition of macro ‘memset’
  195 | #define memset(s, c, count) __builtin_memset(s, c, count)
      |                                              ^
net/bluetooth/l2cap_core.c: In function ‘l2cap_ecred_reconfigure’:
net/bluetooth/l2cap_core.c:7114:18: error: expected expression before ‘struct’
 7114 |  DEFINE_RAW_FLEX(struct l2cap_ecred_reconf_req, pdu, scid, 1);
      |                  ^~~~~~
net/bluetooth/l2cap_core.c:7116:2: error: ‘pdu’ undeclared (first use in this function)
 7116 |  pdu->mtu = cpu_to_le16(chan->imtu);
      |  ^~~
cc1: some warnings being treated as errors
make[4]: *** [scripts/Makefile.build:244: net/bluetooth/l2cap_core.o] Error 1
make[3]: *** [scripts/Makefile.build:485: net/bluetooth] Error 2
make[2]: *** [scripts/Makefile.build:485: net] Error 2
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [/github/workspace/src/src/Makefile:1919: .] Error 2
make: *** [Makefile:240: __sub-make] Error 2
##############################
Test: TestRunnerSetup - FAIL
Desc: Setup kernel and bluez for test-runner
Output:
Kernel: 
net/bluetooth/l2cap_core.c: In function ‘l2cap_ecred_conn_req’:
net/bluetooth/l2cap_core.c:5000:2: error: implicit declaration of function ‘DEFINE_RAW_FLEX’; did you mean ‘DEFINE_FLEX’? [-Werror=implicit-function-declaration]
 5000 |  DEFINE_RAW_FLEX(struct l2cap_ecred_conn_rsp, pdu, dcid, L2CAP_ECRED_MAX_CID);
      |  ^~~~~~~~~~~~~~~
      |  DEFINE_FLEX
net/bluetooth/l2cap_core.c:5000:18: error: expected expression before ‘struct’
 5000 |  DEFINE_RAW_FLEX(struct l2cap_ecred_conn_rsp, pdu, dcid, L2CAP_ECRED_MAX_CID);
      |                  ^~~~~~
net/bluetooth/l2cap_core.c:5048:9: error: ‘pdu’ undeclared (first use in this function)
 5048 |  memset(pdu, 0, sizeof(*pdu));
      |         ^~~
net/bluetooth/l2cap_core.c:5048:9: note: each undeclared identifier is reported only once for each function it appears in
net/bluetooth/l2cap_core.c: In function ‘l2cap_ecred_reconfigure’:
net/bluetooth/l2cap_core.c:7114:18: error: expected expression before ‘struct’
 7114 |  DEFINE_RAW_FLEX(struct l2cap_ecred_reconf_req, pdu, scid, 1);
      |                  ^~~~~~
net/bluetooth/l2cap_core.c:7116:2: error: ‘pdu’ undeclared (first use in this function)
 7116 |  pdu->mtu = cpu_to_le16(chan->imtu);
      |  ^~~
cc1: some warnings being treated as errors
make[4]: *** [scripts/Makefile.build:244: net/bluetooth/l2cap_core.o] Error 1
make[4]: *** Waiting for unfinished jobs....
make[3]: *** [scripts/Makefile.build:485: net/bluetooth] Error 2
make[2]: *** [scripts/Makefile.build:485: net] Error 2
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [/github/workspace/src/src/Makefile:1919: .] Error 2
make: *** [Makefile:240: __sub-make] Error 2
##############################
Test: TestRunner_l2cap-tester - FAIL
Desc: Run l2cap-tester with test-runner
Output:

Could not access KVM kernel module: No such file or directory
qemu-system-x86_64: failed to initialize KVM: No such file or directory
qemu-system-x86_64: Back to tcg accelerator
qemu: could not open kernel file '/github/workspace/src/src/arch/x86/boot/bzImage': No such file or directory
##############################
Test: TestRunner_iso-tester - FAIL
Desc: Run iso-tester with test-runner
Output:

Could not access KVM kernel module: No such file or directory
qemu-system-x86_64: failed to initialize KVM: No such file or directory
qemu-system-x86_64: Back to tcg accelerator
qemu: could not open kernel file '/github/workspace/src/src/arch/x86/boot/bzImage': No such file or directory
##############################
Test: TestRunner_bnep-tester - FAIL
Desc: Run bnep-tester with test-runner
Output:

Could not access KVM kernel module: No such file or directory
qemu-system-x86_64: failed to initialize KVM: No such file or directory
qemu-system-x86_64: Back to tcg accelerator
qemu: could not open kernel file '/github/workspace/src/src/arch/x86/boot/bzImage': No such file or directory
##############################
Test: TestRunner_mgmt-tester - FAIL
Desc: Run mgmt-tester with test-runner
Output:

Could not access KVM kernel module: No such file or directory
qemu-system-x86_64: failed to initialize KVM: No such file or directory
qemu-system-x86_64: Back to tcg accelerator
qemu: could not open kernel file '/github/workspace/src/src/arch/x86/boot/bzImage': No such file or directory
##############################
Test: TestRunner_rfcomm-tester - FAIL
Desc: Run rfcomm-tester with test-runner
Output:

Could not access KVM kernel module: No such file or directory
qemu-system-x86_64: failed to initialize KVM: No such file or directory
qemu-system-x86_64: Back to tcg accelerator
qemu: could not open kernel file '/github/workspace/src/src/arch/x86/boot/bzImage': No such file or directory
##############################
Test: TestRunner_sco-tester - FAIL
Desc: Run sco-tester with test-runner
Output:

Could not access KVM kernel module: No such file or directory
qemu-system-x86_64: failed to initialize KVM: No such file or directory
qemu-system-x86_64: Back to tcg accelerator
qemu: could not open kernel file '/github/workspace/src/src/arch/x86/boot/bzImage': No such file or directory
##############################
Test: TestRunner_ioctl-tester - FAIL
Desc: Run ioctl-tester with test-runner
Output:

Could not access KVM kernel module: No such file or directory
qemu-system-x86_64: failed to initialize KVM: No such file or directory
qemu-system-x86_64: Back to tcg accelerator
qemu: could not open kernel file '/github/workspace/src/src/arch/x86/boot/bzImage': No such file or directory
##############################
Test: TestRunner_mesh-tester - FAIL
Desc: Run mesh-tester with test-runner
Output:

Could not access KVM kernel module: No such file or directory
qemu-system-x86_64: failed to initialize KVM: No such file or directory
qemu-system-x86_64: Back to tcg accelerator
qemu: could not open kernel file '/github/workspace/src/src/arch/x86/boot/bzImage': No such file or directory
##############################
Test: TestRunner_smp-tester - FAIL
Desc: Run smp-tester with test-runner
Output:

Could not access KVM kernel module: No such file or directory
qemu-system-x86_64: failed to initialize KVM: No such file or directory
qemu-system-x86_64: Back to tcg accelerator
qemu: could not open kernel file '/github/workspace/src/src/arch/x86/boot/bzImage': No such file or directory
##############################
Test: TestRunner_userchan-tester - FAIL
Desc: Run userchan-tester with test-runner
Output:

Could not access KVM kernel module: No such file or directory
qemu-system-x86_64: failed to initialize KVM: No such file or directory
qemu-system-x86_64: Back to tcg accelerator
qemu: could not open kernel file '/github/workspace/src/src/arch/x86/boot/bzImage': No such file or directory
##############################
Test: IncrementalBuild - FAIL
Desc: Incremental build with the patches in the series
Output:
[v2,next] Bluetooth: L2CAP: Avoid -Wflex-array-member-not-at-end warnings

net/bluetooth/l2cap_core.c: In function ‘l2cap_ecred_conn_req’:
net/bluetooth/l2cap_core.c:5000:2: error: implicit declaration of function ‘DEFINE_RAW_FLEX’; did you mean ‘DEFINE_FLEX’? [-Werror=implicit-function-declaration]
 5000 |  DEFINE_RAW_FLEX(struct l2cap_ecred_conn_rsp, pdu, dcid, L2CAP_ECRED_MAX_CID);
      |  ^~~~~~~~~~~~~~~
      |  DEFINE_FLEX
net/bluetooth/l2cap_core.c:5000:18: error: expected expression before ‘struct’
 5000 |  DEFINE_RAW_FLEX(struct l2cap_ecred_conn_rsp, pdu, dcid, L2CAP_ECRED_MAX_CID);
      |                  ^~~~~~
net/bluetooth/l2cap_core.c:5048:9: error: ‘pdu’ undeclared (first use in this function)
 5048 |  memset(pdu, 0, sizeof(*pdu));
      |         ^~~
net/bluetooth/l2cap_core.c:5048:9: note: each undeclared identifier is reported only once for each function it appears in
net/bluetooth/l2cap_core.c: In function ‘l2cap_ecred_reconfigure’:
net/bluetooth/l2cap_core.c:7114:18: error: expected expression before ‘struct’
 7114 |  DEFINE_RAW_FLEX(struct l2cap_ecred_reconf_req, pdu, scid, 1);
      |                  ^~~~~~
net/bluetooth/l2cap_core.c:7116:2: error: ‘pdu’ undeclared (first use in this function)
 7116 |  pdu->mtu = cpu_to_le16(chan->imtu);
      |  ^~~
cc1: some warnings being treated as errors
make[4]: *** [scripts/Makefile.build:244: net/bluetooth/l2cap_core.o] Error 1
make[3]: *** [scripts/Makefile.build:485: net/bluetooth] Error 2
make[2]: *** [scripts/Makefile.build:485: net] Error 2
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [/github/workspace/src/src/Makefile:1919: .] Error 2
make: *** [Makefile:240: __sub-make] Error 2


---
Regards,
Linux Bluetooth

Luiz Augusto von Dentz March 27, 2024, 4:55 p.m. UTC | #2

Hi Gustavo,

On Wed, Mar 27, 2024 at 12:23 PM Gustavo A. R. Silva
<[e-mail]> wrote:
>
> -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting
> ready to enable it globally.

Which tree is this base on, I just rebased bluetooth-next on top of
net-next but it looks like CI is still failing to build it, so either
we don't have all the dependencies already in net-next or perhaps you
had it submit while the tree had not been updated.

> There are currently a couple of objects (`req` and `rsp`), in a couple
> of structures, that contain flexible structures (`struct l2cap_ecred_conn_req`
> and `struct l2cap_ecred_conn_rsp`), for example:
>
> struct l2cap_ecred_rsp_data {
>         struct {
>                 struct l2cap_ecred_conn_rsp rsp;
>                 __le16 scid[L2CAP_ECRED_MAX_CID];
>         } __packed pdu;
>         int count;
> };
>
> in the struct above, `struct l2cap_ecred_conn_rsp` is a flexible
> structure:
>
> struct l2cap_ecred_conn_rsp {
>         __le16 mtu;
>         __le16 mps;
>         __le16 credits;
>         __le16 result;
>         __le16 dcid[];
> };
>
> So, in order to avoid ending up with a flexible-array member in the
> middle of another structure, we use the `struct_group_tagged()` (and
> `__struct_group()` when the flexible structure is `__packed`) helper
> to separate the flexible array from the rest of the members in the
> flexible structure:
>
> struct l2cap_ecred_conn_rsp {
>         struct_group_tagged(l2cap_ecred_conn_rsp_hdr, hdr,
>
>         ... the rest of members
>
>         );
>         __le16 dcid[];
> };
>
> With the change described above, we now declare objects of the type of
> the tagged struct, in this example `struct l2cap_ecred_conn_rsp_hdr`,
> without embedding flexible arrays in the middle of other structures:
>
> struct l2cap_ecred_rsp_data {
>         struct {
>                 struct l2cap_ecred_conn_rsp_hdr rsp;
>                 __le16 scid[L2CAP_ECRED_MAX_CID];
>         } __packed pdu;
>         int count;
> };
>
> Also, when the flexible-array member needs to be accessed, we use
> `container_of()` to retrieve a pointer to the flexible structure.
>
> We also use the `DEFINE_RAW_FLEX()` helper for a couple of on-stack
> definitions of a flexible structure where the size of the flexible-array
> member is known at compile-time.
>
> So, with these changes, fix the following warnings:
> net/bluetooth/l2cap_core.c:1260:45: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
> net/bluetooth/l2cap_core.c:3740:45: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
> net/bluetooth/l2cap_core.c:4999:45: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
> net/bluetooth/l2cap_core.c:7116:47: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
>
> Link: https://github.com/KSPP/linux/issues/202
> Signed-off-by: Gustavo A. R. Silva <[e-mail]>
> ---
> Changes in v2:
>  - Add a couple of code comments.
>
> v1:
>  - Link: https://lore.kernel.org/linux-hardening/ZgMpynzZ8FltPCi3@neat/
>
> Hi!
>
> I wonder if `struct l2cap_ecred_conn_rsp` should also be `__packed`.
>
> Thanks
>  - Gustavo
>
>  include/net/bluetooth/l2cap.h | 22 +++++++++++------
>  net/bluetooth/l2cap_core.c    | 46 ++++++++++++++++-------------------
>  2 files changed, 35 insertions(+), 33 deletions(-)
>
> diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
> index a4278aa618ab..7d4a3e766e7b 100644
> --- a/include/net/bluetooth/l2cap.h
> +++ b/include/net/bluetooth/l2cap.h
> @@ -463,18 +463,24 @@ struct l2cap_le_credits {
>  #define L2CAP_ECRED_MAX_CID            5
>
>  struct l2cap_ecred_conn_req {
> -       __le16 psm;
> -       __le16 mtu;
> -       __le16 mps;
> -       __le16 credits;
> +       /* New members must be added within the struct_group() macro below. */
> +       __struct_group(l2cap_ecred_conn_req_hdr, hdr, __packed,
> +               __le16 psm;
> +               __le16 mtu;
> +               __le16 mps;
> +               __le16 credits;
> +       );
>         __le16 scid[];
>  } __packed;
>
>  struct l2cap_ecred_conn_rsp {
> -       __le16 mtu;
> -       __le16 mps;
> -       __le16 credits;
> -       __le16 result;
> +       /* New members must be added within the struct_group() macro below. */
> +       struct_group_tagged(l2cap_ecred_conn_rsp_hdr, hdr,
> +               __le16 mtu;
> +               __le16 mps;
> +               __le16 credits;
> +               __le16 result;
> +       );
>         __le16 dcid[];
>  };
>
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 467b242d8be0..bf087eca489e 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -1257,7 +1257,7 @@ static void l2cap_le_connect(struct l2cap_chan *chan)
>
>  struct l2cap_ecred_conn_data {
>         struct {
> -               struct l2cap_ecred_conn_req req;
> +               struct l2cap_ecred_conn_req_hdr req;
>                 __le16 scid[5];
>         } __packed pdu;
>         struct l2cap_chan *chan;
> @@ -3737,7 +3737,7 @@ static void l2cap_ecred_list_defer(struct l2cap_chan *chan, void *data)
>
>  struct l2cap_ecred_rsp_data {
>         struct {
> -               struct l2cap_ecred_conn_rsp rsp;
> +               struct l2cap_ecred_conn_rsp_hdr rsp;
>                 __le16 scid[L2CAP_ECRED_MAX_CID];
>         } __packed pdu;
>         int count;
> @@ -3746,6 +3746,8 @@ struct l2cap_ecred_rsp_data {
>  static void l2cap_ecred_rsp_defer(struct l2cap_chan *chan, void *data)
>  {
>         struct l2cap_ecred_rsp_data *rsp = data;
> +       struct l2cap_ecred_conn_rsp *rsp_flex =
> +               container_of(&rsp->pdu.rsp, struct l2cap_ecred_conn_rsp, hdr);
>
>         if (test_bit(FLAG_ECRED_CONN_REQ_SENT, &chan->flags))
>                 return;
> @@ -3755,7 +3757,7 @@ static void l2cap_ecred_rsp_defer(struct l2cap_chan *chan, void *data)
>
>         /* Include all channels pending with the same ident */
>         if (!rsp->pdu.rsp.result)
> -               rsp->pdu.rsp.dcid[rsp->count++] = cpu_to_le16(chan->scid);
> +               rsp_flex->dcid[rsp->count++] = cpu_to_le16(chan->scid);
>         else
>                 l2cap_chan_del(chan, ECONNRESET);
>  }
> @@ -4995,10 +4997,7 @@ static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn,
>                                        u8 *data)
>  {
>         struct l2cap_ecred_conn_req *req = (void *) data;
> -       struct {
> -               struct l2cap_ecred_conn_rsp rsp;
> -               __le16 dcid[L2CAP_ECRED_MAX_CID];
> -       } __packed pdu;
> +       DEFINE_RAW_FLEX(struct l2cap_ecred_conn_rsp, pdu, dcid, L2CAP_ECRED_MAX_CID);
>         struct l2cap_chan *chan, *pchan;
>         u16 mtu, mps;
>         __le16 psm;
> @@ -5017,7 +5016,7 @@ static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn,
>         cmd_len -= sizeof(*req);
>         num_scid = cmd_len / sizeof(u16);
>
> -       if (num_scid > ARRAY_SIZE(pdu.dcid)) {
> +       if (num_scid > L2CAP_ECRED_MAX_CID) {
>                 result = L2CAP_CR_LE_INVALID_PARAMS;
>                 goto response;
>         }
> @@ -5046,7 +5045,7 @@ static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn,
>
>         BT_DBG("psm 0x%2.2x mtu %u mps %u", __le16_to_cpu(psm), mtu, mps);
>
> -       memset(&pdu, 0, sizeof(pdu));
> +       memset(pdu, 0, sizeof(*pdu));
>
>         /* Check if we have socket listening on psm */
>         pchan = l2cap_global_chan_by_psm(BT_LISTEN, psm, &conn->hcon->src,
> @@ -5072,8 +5071,8 @@ static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn,
>
>                 BT_DBG("scid[%d] 0x%4.4x", i, scid);
>
> -               pdu.dcid[i] = 0x0000;
> -               len += sizeof(*pdu.dcid);
> +               pdu->dcid[i] = 0x0000;
> +               len += sizeof(*pdu->dcid);
>
>                 /* Check for valid dynamic CID range */
>                 if (scid < L2CAP_CID_DYN_START || scid > L2CAP_CID_LE_DYN_END) {
> @@ -5107,13 +5106,13 @@ static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn,
>                 l2cap_ecred_init(chan, __le16_to_cpu(req->credits));
>
>                 /* Init response */
> -               if (!pdu.rsp.credits) {
> -                       pdu.rsp.mtu = cpu_to_le16(chan->imtu);
> -                       pdu.rsp.mps = cpu_to_le16(chan->mps);
> -                       pdu.rsp.credits = cpu_to_le16(chan->rx_credits);
> +               if (!pdu->credits) {
> +                       pdu->mtu = cpu_to_le16(chan->imtu);
> +                       pdu->mps = cpu_to_le16(chan->mps);
> +                       pdu->credits = cpu_to_le16(chan->rx_credits);
>                 }
>
> -               pdu.dcid[i] = cpu_to_le16(chan->scid);
> +               pdu->dcid[i] = cpu_to_le16(chan->scid);
>
>                 __set_chan_timer(chan, chan->ops->get_sndtimeo(chan));
>
> @@ -5135,13 +5134,13 @@ static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn,
>         l2cap_chan_put(pchan);
>
>  response:
> -       pdu.rsp.result = cpu_to_le16(result);
> +       pdu->result = cpu_to_le16(result);
>
>         if (defer)
>                 return 0;
>
>         l2cap_send_cmd(conn, cmd->ident, L2CAP_ECRED_CONN_RSP,
> -                      sizeof(pdu.rsp) + len, &pdu);
> +                      sizeof(*pdu) + len, pdu);
>
>         return 0;
>  }
> @@ -7112,14 +7111,11 @@ EXPORT_SYMBOL_GPL(l2cap_chan_connect);
>  static void l2cap_ecred_reconfigure(struct l2cap_chan *chan)
>  {
>         struct l2cap_conn *conn = chan->conn;
> -       struct {
> -               struct l2cap_ecred_reconf_req req;
> -               __le16 scid;
> -       } pdu;
> +       DEFINE_RAW_FLEX(struct l2cap_ecred_reconf_req, pdu, scid, 1);
>
> -       pdu.req.mtu = cpu_to_le16(chan->imtu);
> -       pdu.req.mps = cpu_to_le16(chan->mps);
> -       pdu.scid    = cpu_to_le16(chan->scid);
> +       pdu->mtu = cpu_to_le16(chan->imtu);
> +       pdu->mps = cpu_to_le16(chan->mps);
> +       pdu->scid[0] = cpu_to_le16(chan->scid);
>
>         chan->ident = l2cap_get_ident(conn);
>
> --
> 2.34.1
>

Gustavo A. R. Silva March 27, 2024, 5:08 p.m. UTC | #3

Hi!

On 3/27/24 10:55, Luiz Augusto von Dentz wrote:
> Hi Gustavo,
> 
> On Wed, Mar 27, 2024 at 12:23 PM Gustavo A. R. Silva
> <[e-mail]> wrote:
>>
>> -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting
>> ready to enable it globally.
> 
> Which tree is this base on, I just rebased bluetooth-next on top of
> net-next but it looks like CI is still failing to build it, so either
> we don't have all the dependencies already in net-next or perhaps you
> had it submit while the tree had not been updated.

This is based off of linux-next.

I think net-next is missing this commit in v6.9-rc1:

d8e45f2929b9 "overflow: Change DEFINE_FLEX to take __counted_by member")

https://git.kernel.org/linus/d8e45f2929b9

Thanks
--
Gustavo

Kees Cook March 28, 2024, 5:28 a.m. UTC | #4

On March 27, 2024 11:08:33 AM MDT, "Gustavo A. R. Silva" <[e-mail]> wrote:
>Hi!
>
>On 3/27/24 10:55, Luiz Augusto von Dentz wrote:
>> Hi Gustavo,
>> 
>> On Wed, Mar 27, 2024 at 12:23 PM Gustavo A. R. Silva
>> <[e-mail]> wrote:
>>> 
>>> -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting
>>> ready to enable it globally.
>> 
>> Which tree is this base on, I just rebased bluetooth-next on top of
>> net-next but it looks like CI is still failing to build it, so either
>> we don't have all the dependencies already in net-next or perhaps you
>> had it submit while the tree had not been updated.
>
>This is based off of linux-next.
>
>I think net-next is missing this commit in v6.9-rc1:
>
>d8e45f2929b9 "overflow: Change DEFINE_FLEX to take __counted_by member")
>
>https://git.kernel.org/linus/d8e45f2929b9

Just FYI, that is in rc1. (I sent it late to avoid a netdev collision.)

Gustavo A. R. Silva March 28, 2024, 5:51 a.m. UTC | #5

On 27/03/24 23:28, Kees Cook wrote:
> 
> 
> On March 27, 2024 11:08:33 AM MDT, "Gustavo A. R. Silva" <[e-mail]> wrote:
>> Hi!
>>
>> On 3/27/24 10:55, Luiz Augusto von Dentz wrote:
>>> Hi Gustavo,
>>>
>>> On Wed, Mar 27, 2024 at 12:23 PM Gustavo A. R. Silva
>>> <[e-mail]> wrote:
>>>>
>>>> -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting
>>>> ready to enable it globally.
>>>
>>> Which tree is this base on, I just rebased bluetooth-next on top of
>>> net-next but it looks like CI is still failing to build it, so either
>>> we don't have all the dependencies already in net-next or perhaps you
>>> had it submit while the tree had not been updated.
>>
>> This is based off of linux-next.
>>
>> I think net-next is missing this commit in v6.9-rc1:
>>
>> d8e45f2929b9 "overflow: Change DEFINE_FLEX to take __counted_by member")
>>
>> https://git.kernel.org/linus/d8e45f2929b9
> 
> Just FYI, that is in rc1. (I sent it late to avoid a netdev collision.)
> 

Yep.

They haven't pulled all the changes from mainline up to -rc1, yet:

https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/log/

--
Gustavo

[e-mail] April 8, 2024, 10:11 p.m. UTC | #6

Hello:

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

On Wed, 27 Mar 2024 10:23:51 -0600 you wrote:
> -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting
> ready to enable it globally.
> 
> There are currently a couple of objects (`req` and `rsp`), in a couple
> of structures, that contain flexible structures (`struct l2cap_ecred_conn_req`
> and `struct l2cap_ecred_conn_rsp`), for example:
> 
> [...]

Here is the summary with links:
  - [v2,next] Bluetooth: L2CAP: Avoid -Wflex-array-member-not-at-end warnings
    https://git.kernel.org/bluetooth/bluetooth-next/c/215c4704208b

You are awesome, thank you!

Patch

diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index a4278aa618ab..7d4a3e766e7b 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -463,18 +463,24 @@  struct l2cap_le_credits {
 #define L2CAP_ECRED_MAX_CID		5
 
 struct l2cap_ecred_conn_req {
-	__le16 psm;
-	__le16 mtu;
-	__le16 mps;
-	__le16 credits;
+	/* New members must be added within the struct_group() macro below. */
+	__struct_group(l2cap_ecred_conn_req_hdr, hdr, __packed,
+		__le16 psm;
+		__le16 mtu;
+		__le16 mps;
+		__le16 credits;
+	);
 	__le16 scid[];
 } __packed;
 
 struct l2cap_ecred_conn_rsp {
-	__le16 mtu;
-	__le16 mps;
-	__le16 credits;
-	__le16 result;
+	/* New members must be added within the struct_group() macro below. */
+	struct_group_tagged(l2cap_ecred_conn_rsp_hdr, hdr,
+		__le16 mtu;
+		__le16 mps;
+		__le16 credits;
+		__le16 result;
+	);
 	__le16 dcid[];
 };
 
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 467b242d8be0..bf087eca489e 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1257,7 +1257,7 @@  static void l2cap_le_connect(struct l2cap_chan *chan)
 
 struct l2cap_ecred_conn_data {
 	struct {
-		struct l2cap_ecred_conn_req req;
+		struct l2cap_ecred_conn_req_hdr req;
 		__le16 scid[5];
 	} __packed pdu;
 	struct l2cap_chan *chan;
@@ -3737,7 +3737,7 @@  static void l2cap_ecred_list_defer(struct l2cap_chan *chan, void *data)
 
 struct l2cap_ecred_rsp_data {
 	struct {
-		struct l2cap_ecred_conn_rsp rsp;
+		struct l2cap_ecred_conn_rsp_hdr rsp;
 		__le16 scid[L2CAP_ECRED_MAX_CID];
 	} __packed pdu;
 	int count;
@@ -3746,6 +3746,8 @@  struct l2cap_ecred_rsp_data {
 static void l2cap_ecred_rsp_defer(struct l2cap_chan *chan, void *data)
 {
 	struct l2cap_ecred_rsp_data *rsp = data;
+	struct l2cap_ecred_conn_rsp *rsp_flex =
+		container_of(&rsp->pdu.rsp, struct l2cap_ecred_conn_rsp, hdr);
 
 	if (test_bit(FLAG_ECRED_CONN_REQ_SENT, &chan->flags))
 		return;
@@ -3755,7 +3757,7 @@  static void l2cap_ecred_rsp_defer(struct l2cap_chan *chan, void *data)
 
 	/* Include all channels pending with the same ident */
 	if (!rsp->pdu.rsp.result)
-		rsp->pdu.rsp.dcid[rsp->count++] = cpu_to_le16(chan->scid);
+		rsp_flex->dcid[rsp->count++] = cpu_to_le16(chan->scid);
 	else
 		l2cap_chan_del(chan, ECONNRESET);
 }
@@ -4995,10 +4997,7 @@  static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn,
 				       u8 *data)
 {
 	struct l2cap_ecred_conn_req *req = (void *) data;
-	struct {
-		struct l2cap_ecred_conn_rsp rsp;
-		__le16 dcid[L2CAP_ECRED_MAX_CID];
-	} __packed pdu;
+	DEFINE_RAW_FLEX(struct l2cap_ecred_conn_rsp, pdu, dcid, L2CAP_ECRED_MAX_CID);
 	struct l2cap_chan *chan, *pchan;
 	u16 mtu, mps;
 	__le16 psm;
@@ -5017,7 +5016,7 @@  static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn,
 	cmd_len -= sizeof(*req);
 	num_scid = cmd_len / sizeof(u16);
 
-	if (num_scid > ARRAY_SIZE(pdu.dcid)) {
+	if (num_scid > L2CAP_ECRED_MAX_CID) {
 		result = L2CAP_CR_LE_INVALID_PARAMS;
 		goto response;
 	}
@@ -5046,7 +5045,7 @@  static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn,
 
 	BT_DBG("psm 0x%2.2x mtu %u mps %u", __le16_to_cpu(psm), mtu, mps);
 
-	memset(&pdu, 0, sizeof(pdu));
+	memset(pdu, 0, sizeof(*pdu));
 
 	/* Check if we have socket listening on psm */
 	pchan = l2cap_global_chan_by_psm(BT_LISTEN, psm, &conn->hcon->src,
@@ -5072,8 +5071,8 @@  static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn,
 
 		BT_DBG("scid[%d] 0x%4.4x", i, scid);
 
-		pdu.dcid[i] = 0x0000;
-		len += sizeof(*pdu.dcid);
+		pdu->dcid[i] = 0x0000;
+		len += sizeof(*pdu->dcid);
 
 		/* Check for valid dynamic CID range */
 		if (scid < L2CAP_CID_DYN_START || scid > L2CAP_CID_LE_DYN_END) {
@@ -5107,13 +5106,13 @@  static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn,
 		l2cap_ecred_init(chan, __le16_to_cpu(req->credits));
 
 		/* Init response */
-		if (!pdu.rsp.credits) {
-			pdu.rsp.mtu = cpu_to_le16(chan->imtu);
-			pdu.rsp.mps = cpu_to_le16(chan->mps);
-			pdu.rsp.credits = cpu_to_le16(chan->rx_credits);
+		if (!pdu->credits) {
+			pdu->mtu = cpu_to_le16(chan->imtu);
+			pdu->mps = cpu_to_le16(chan->mps);
+			pdu->credits = cpu_to_le16(chan->rx_credits);
 		}
 
-		pdu.dcid[i] = cpu_to_le16(chan->scid);
+		pdu->dcid[i] = cpu_to_le16(chan->scid);
 
 		__set_chan_timer(chan, chan->ops->get_sndtimeo(chan));
 
@@ -5135,13 +5134,13 @@  static inline int l2cap_ecred_conn_req(struct l2cap_conn *conn,
 	l2cap_chan_put(pchan);
 
 response:
-	pdu.rsp.result = cpu_to_le16(result);
+	pdu->result = cpu_to_le16(result);
 
 	if (defer)
 		return 0;
 
 	l2cap_send_cmd(conn, cmd->ident, L2CAP_ECRED_CONN_RSP,
-		       sizeof(pdu.rsp) + len, &pdu);
+		       sizeof(*pdu) + len, pdu);
 
 	return 0;
 }
@@ -7112,14 +7111,11 @@  EXPORT_SYMBOL_GPL(l2cap_chan_connect);
 static void l2cap_ecred_reconfigure(struct l2cap_chan *chan)
 {
 	struct l2cap_conn *conn = chan->conn;
-	struct {
-		struct l2cap_ecred_reconf_req req;
-		__le16 scid;
-	} pdu;
+	DEFINE_RAW_FLEX(struct l2cap_ecred_reconf_req, pdu, scid, 1);
 
-	pdu.req.mtu = cpu_to_le16(chan->imtu);
-	pdu.req.mps = cpu_to_le16(chan->mps);
-	pdu.scid    = cpu_to_le16(chan->scid);
+	pdu->mtu = cpu_to_le16(chan->imtu);
+	pdu->mps = cpu_to_le16(chan->mps);
+	pdu->scid[0] = cpu_to_le16(chan->scid);
 
 	chan->ident = l2cap_get_ident(conn);