Bug 16092 - Compilers may ignore overflow checks - Fix tautological-compare warnings
Summary: Compilers may ignore overflow checks - Fix tautological-compare warnings
Status: RESOLVED FIXED
Alias: None
Product: Samba 4.1 and newer
Classification: Unclassified
Component: Build (show other bugs)
Version: 4.24.3
Hardware: All All
: P5 normal (vote)
Target Milestone: ---
Assignee: Samba release manager
QA Contact: Samba QA Contact
URL: https://gitlab.com/samba-team/samba/-...
Keywords:
Depends on:
Blocks:
 
Reported: 2026-05-28 09:16 UTC by Stefan Metzmacher
Modified: 2026-06-08 18:08 UTC (History)
1 user (show)

See Also:

Attachments
Proposed patch for V4.23 (20.73 KB, patch)
2026-05-29 01:56 UTC, Gary Lockyer 		metze: review+
gary: ci-passed+
Details
Proposed patch for V4.24 (20.73 KB, patch)
2026-05-29 01:56 UTC, Gary Lockyer 		metze: review+
gary: ci-passed+
Details
View All Add an attachment (proposed patch, testcase, etc.)

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Description Stefan Metzmacher 2026-05-28 09:16:31 UTC 
The wrapping of pointer arithmetic is undefined behavior. Clang from version 20
onwards will treat an overflow check of the following form:
    ptr + offset < ptr
as always evaluating to false
Comment 1 Samba QA Contact 2026-05-28 18:43:03 UTC 
This bug was referenced in samba master:

2e53f7196f45d28689f25a57fa84995eceee4585
fae07aecfed5b3b8f53bbad4500a0ba4d8785da1
343faf508b5328c239896db8a5bb8f6333f75599
d80c9dac0765a5b114718450ec5a062cd2b6f86f
769cf0a0ddb5c7af65afa5b764c24a3416025745
3287641bbf3360c8241db090781ebc2d5febbc96
b58d7045d5444d70db58d07d7746006ea1b9ecfb
3485f58ea1c2a4013b0ab60c1ddee0faa4eb3eea
fb188140357a5d8796c47c5fd88c8a25117bda8e
Comment 2 Gary Lockyer 2026-05-29 01:56:05 UTC 
Created attachment 19000 [details]
Proposed patch for V4.23

Job paused in CI

This job is stuck because of one of the following problems. There are no active runners online, no runners for the protected branch , or no runners that match all of the job's tags: docker samba-ci-private
Go to project CI settings 

https://gitlab.com/samba-team/devel/samba/-/pipelines/2560467600

But as the 3 preceding steps have succeeded I'm taking this as a pass.
Comment 3 Gary Lockyer 2026-05-29 01:56:58 UTC 
Created attachment 19001 [details]
Proposed patch for V4.24
Comment 4 Samba QA Contact 2026-06-08 17:54:04 UTC 
This bug was referenced in samba v4-24-test:

bf154a3ed480bacc5bc5452311892ef5ec84405c
7212717cee782af15166acb41db0128ad478de40
b394b0845d1f4f2639a2e5f772491f3638152a49
c99e124aedff59d2fe43cf960c74714198e70296
48ab866b8b3814c7c1dc75b6db7bd082a1320201
e3c8606be10452e77676d357c3afe31dfb786b24
f89835887e1776cd772404956b3217cb15c6fae2
65a87c2e4de9b1a9bfac42ebb602fee0f8965388
b528da253ca7a2db5ee83cd5233037714bf154b5
Comment 5 Samba QA Contact 2026-06-08 18:08:20 UTC 
This bug was referenced in samba v4-23-test:

0129c019f3822f76321e7883ea90d49c3184bc7e
9bed3dc2f912e79787ac3c42e44231a9739a3a8e
4ff95725b48881145fb0e409b65b0a6dcca1044e
3d115fd1c46d69d545e28c2328f2bcadddf6ac80
da619c48c10ab1017f3e454dab6658073780f5f4
2f0fe8c2884870825fcc08054e2b5835337fe56e
f3bef4a8d9fe858751e0040ef01c11eabfe4e799
0d0a209748bb13033d8cc38ea92490c19eef1f43
b1443f70b1173ad1521edacad2be4c4a5be8e3f8