[PW_SID:1126083] [1/2] Bluetooth: L2CAP: avoid maybe-return-locked and add locking annotations

[BluezTestBot]

Replace the maybe-return-locked behavior of
l2cap_get_chan_by_scid/dcid() by doing locking in the caller after NULL
check. This allows the static context analysis to handle this. No
functional change intended.

Add context analysis annotations related to l2cap_chan_lock/unlock().

Signed-off-by: Pauli Virtanen pav@iki.fi

Notes:
Possibly the l2cap_ops::alloc_skb callback should have generally
__must_hold(&chan->lock) and not just in l2cap_sock.c

This would imply l2cap_chan_send() should hold the lock, but trying to
add the annotations reveals l2cap_chan_send is called without chan->lock
from some places:

net/bluetooth/smp.c:589:2: warning: calling function 'l2cap_chan_send' requires holding mutex 'conn->smp->lock' exclusively [-Wthread-safety-analysis]
  589 |         l2cap_chan_send(chan, &msg, 1 + len, NULL);
      |         ^
1 warning generated.
net/bluetooth/6lowpan.c:455:8: warning: calling function 'l2cap_chan_send' requires holding mutex 'chan->lock' exclusively [-Wthread-safety-analysis]
  455 |         err = l2cap_chan_send(chan, &msg, skb->len, NULL);
      |               ^

Don't know now if the context in these places allows l2cap_chan_lock()

include/net/bluetooth/l2cap.h | 2 ++
net/bluetooth/l2cap_core.c | 25 +++++++++++++++++--------
net/bluetooth/l2cap_sock.c | 1 +
3 files changed, 20 insertions(+), 8 deletions(-)

[github-actions]

CheckPatch
Desc: Run checkpatch.pl script
Duration: 1.84 seconds
Result: PASS

[github-actions]

VerifyFixes
Desc: Verify Fixes tag format and validity
Duration: 0.13 seconds
Result: PASS

[github-actions]

VerifySignedoff
Desc: Verify Signed-off-by chain
Duration: 0.13 seconds
Result: PASS

[github-actions]

GitLint
Desc: Run gitlint
Duration: 0.67 seconds
Result: FAIL
Output:

[1/2] Bluetooth: L2CAP: avoid maybe-return-locked and add locking annotations

16: B2 Line has trailing whitespace: "    "
20: B2 Line has trailing whitespace: "    "
21: B1 Line exceeds max length (154>80): "    net/bluetooth/smp.c:589:2: warning: calling function 'l2cap_chan_send' requires holding mutex 'conn->smp->lock' exclusively [-Wthread-safety-analysis]"
25: B1 Line exceeds max length (153>80): "    net/bluetooth/6lowpan.c:455:8: warning: calling function 'l2cap_chan_send' requires holding mutex 'chan->lock' exclusively [-Wthread-safety-analysis]"
28: B2 Line has trailing whitespace: "    "

[github-actions]

SubjectPrefix
Desc: Check subject contains "Bluetooth" prefix
Duration: 0.26 seconds
Result: PASS

[github-actions]

BuildKernel
Desc: Build Kernel for Bluetooth
Duration: 25.93 seconds
Result: PASS

[github-actions]

CheckAllWarning
Desc: Run linux kernel with all warning enabled
Duration: 28.09 seconds
Result: PASS

[github-actions]

CheckSparse
Desc: Run sparse tool with linux kernel
Duration: 26.96 seconds
Result: PASS

[github-actions]

BuildKernel32
Desc: Build 32bit Kernel for Bluetooth
Duration: 25.12 seconds
Result: PASS

[github-actions]

CheckKernelLLVM
Desc: Build kernel with LLVM + context analysis
Duration: 0.00 seconds
Result: SKIP
Output:

Clang not found

[github-actions]

TestRunnerSetup
Desc: Setup kernel and bluez for test-runner
Duration: 464.52 seconds
Result: PASS

[github-actions]

TestRunner_l2cap-tester
Desc: Run l2cap-tester with test-runner
Duration: 59.28 seconds
Result: FAIL
Output:

Total: 96, Passed: 95 (99.0%), Failed: 1, Not Run: 0

Failed Test Cases
L2CAP BR/EDR Server - Set PHY 2M                     Failed       0.252 seconds

[github-actions]

TestRunner_iso-tester
Desc: Run iso-tester with test-runner
Duration: 85.82 seconds
Result: PASS

[github-actions]

TestRunner_bnep-tester
Desc: Run bnep-tester with test-runner
Duration: 19.07 seconds
Result: PASS

[github-actions]

TestRunner_mgmt-tester
Desc: Run mgmt-tester with test-runner
Duration: 213.90 seconds
Result: FAIL
Output:

Total: 494, Passed: 489 (99.0%), Failed: 1, Not Run: 4

Failed Test Cases
Read Exp Feature - Success                           Failed       0.244 seconds

[github-actions]

TestRunner_rfcomm-tester
Desc: Run rfcomm-tester with test-runner
Duration: 26.06 seconds
Result: PASS

[github-actions]

TestRunner_sco-tester
Desc: Run sco-tester with test-runner
Duration: 32.35 seconds
Result: PASS

[github-actions]

TestRunner_ioctl-tester
Desc: Run ioctl-tester with test-runner
Duration: 26.44 seconds
Result: PASS

[github-actions]

TestRunner_mesh-tester
Desc: Run mesh-tester with test-runner
Duration: 26.05 seconds
Result: FAIL
Output:

Total: 10, Passed: 8 (80.0%), Failed: 2, Not Run: 0

Failed Test Cases
Mesh - Send cancel - 1                               Timed out    2.622 seconds
Mesh - Send cancel - 2                               Timed out    1.989 seconds

[github-actions]

TestRunner_smp-tester
Desc: Run smp-tester with test-runner
Duration: 23.08 seconds
Result: PASS

[github-actions]

TestRunner_userchan-tester
Desc: Run userchan-tester with test-runner
Duration: 19.71 seconds
Result: PASS

[github-actions]

TestRunner_6lowpan-tester
Desc: Run 6lowpan-tester with test-runner
Duration: 22.91 seconds
Result: PASS

[github-actions]

IncrementalBuild
Desc: Incremental build with the patches in the series
Duration: 25.30 seconds
Result: PASS