* [Bug runtime/23435] New: stapbpf transport layer can swallow a message before exit()
@ 2018-07-19 17:06 serhei.public at gmail dot com
2018-08-09 14:32 ` [Bug bpf/23435] " me at serhei dot io
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: serhei.public at gmail dot com @ 2018-07-19 17:06 UTC (permalink / raw)
To: systemtap
https://sourceware.org/bugzilla/show_bug.cgi?id=23435
Bug ID: 23435
Summary: stapbpf transport layer can swallow a message before
exit()
Product: systemtap
Version: unspecified
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: runtime
Assignee: systemtap at sourceware dot org
Reporter: serhei.public at gmail dot com
Target Milestone: ---
In the following test program:
probe kernel.function("vfs_read") {
printf("a\n"); printf("b\n"); exit()
}
The stapbpf transport layer will see the following:
0: <tag>a
1: </tag>
2: <tag>b
3: </tag>
4: <tag></tag>
Because exit() sets exit_status before stapbpf reads this data, the empty
</tag> on line 1 will trigger the program to exit.
Similarly,
probe kernel.function("vfs_read") {
printf(""); printf("b\n"); exit()
}
will also swallow the second message.
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* [Bug bpf/23435] stapbpf transport layer can swallow a message before exit()
2018-07-19 17:06 [Bug runtime/23435] New: stapbpf transport layer can swallow a message before exit() serhei.public at gmail dot com
@ 2018-08-09 14:32 ` me at serhei dot io
2018-08-21 21:02 ` serhei.public at gmail dot com
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: me at serhei dot io @ 2018-08-09 14:32 UTC (permalink / raw)
To: systemtap
https://sourceware.org/bugzilla/show_bug.cgi?id=23435
Serhei Makarov <me at serhei dot io> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |me at serhei dot io
Component|runtime |bpf
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* [Bug bpf/23435] stapbpf transport layer can swallow a message before exit()
2018-07-19 17:06 [Bug runtime/23435] New: stapbpf transport layer can swallow a message before exit() serhei.public at gmail dot com
2018-08-09 14:32 ` [Bug bpf/23435] " me at serhei dot io
@ 2018-08-21 21:02 ` serhei.public at gmail dot com
2018-08-21 21:22 ` me at serhei dot io
2018-10-24 21:18 ` me at serhei dot io
3 siblings, 0 replies; 5+ messages in thread
From: serhei.public at gmail dot com @ 2018-08-21 21:02 UTC (permalink / raw)
To: systemtap
https://sourceware.org/bugzilla/show_bug.cgi?id=23435
--- Comment #1 from Serhei Makarov <serhei.public at gmail dot com> ---
Looks like this issue depends on PR22330. Once we have a proper transport
framework, we can implement a proper EXIT message instead of multiplexing onto
trace_printk() like this.
I experimented a bit with having exit() send a (much less likely to occur)
non-printing character to make the second testcase work properly, but that
introduces more problems than it solves.
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* [Bug bpf/23435] stapbpf transport layer can swallow a message before exit()
2018-07-19 17:06 [Bug runtime/23435] New: stapbpf transport layer can swallow a message before exit() serhei.public at gmail dot com
2018-08-09 14:32 ` [Bug bpf/23435] " me at serhei dot io
2018-08-21 21:02 ` serhei.public at gmail dot com
@ 2018-08-21 21:22 ` me at serhei dot io
2018-10-24 21:18 ` me at serhei dot io
3 siblings, 0 replies; 5+ messages in thread
From: me at serhei dot io @ 2018-08-21 21:22 UTC (permalink / raw)
To: systemtap
https://sourceware.org/bugzilla/show_bug.cgi?id=23435
Serhei Makarov <me at serhei dot io> changed:
What |Removed |Added
----------------------------------------------------------------------------
Depends on| |22330
Referenced Bugs:
https://sourceware.org/bugzilla/show_bug.cgi?id=22330
[Bug 22330] bpf: generate printf via event tuples, userspace formatting
postprocessing
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* [Bug bpf/23435] stapbpf transport layer can swallow a message before exit()
2018-07-19 17:06 [Bug runtime/23435] New: stapbpf transport layer can swallow a message before exit() serhei.public at gmail dot com
` (2 preceding siblings ...)
2018-08-21 21:22 ` me at serhei dot io
@ 2018-10-24 21:18 ` me at serhei dot io
3 siblings, 0 replies; 5+ messages in thread
From: me at serhei dot io @ 2018-10-24 21:18 UTC (permalink / raw)
To: systemtap
https://sourceware.org/bugzilla/show_bug.cgi?id=23435
Serhei Makarov <me at serhei dot io> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|systemtap at sourceware dot org |me at serhei dot io
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2018-07-19 17:06 [Bug runtime/23435] New: stapbpf transport layer can swallow a message before exit() serhei.public at gmail dot com
2018-08-09 14:32 ` [Bug bpf/23435] " me at serhei dot io
2018-08-21 21:02 ` serhei.public at gmail dot com
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2018-10-24 21:18 ` me at serhei dot io
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