adding op-codes for syscall ipc for shmat/shmdt #7777
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Pending the commit message update, I approve.
We saw this problem on RHEL8. These two OS calls are not defined in the OS headers, but if an application calls either of them, then it can cause a Wrong Answer since the memory hooks don’t intercept correctly.
Unfortunately, our only reliable test case is quite complex, and requires our ppc64le math library.
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@markalle can you please check if this affects v3.0.x or v3.1.x on RHEL8, and if so, please cherry-pick there as well? |
These op codes used to be in bits/ipc.h but were removed in glibc in 2015 with a comment saying they should be defined in internal headers: https://sourceware.org/bugzilla/show_bug.cgi?id=18560 and when glibc uses that syscall it seems to do so from its own definitions: https://github.com/bminor/glibc/search?q=IPCOP_shmat&unscoped_q=IPCOP_shmat So I think using #ifndef and defining them if they're not already defined using the values from glibc is the best option. At IBM it was the testing on redhat 8 that found this as an issue (the opcodes being undefined on the system made it select the left undefined so shmat/shmdt memory events went unintercepted). Signed-off-by: Mark Allen <markalle@us.ibm.com>
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I updated the commit, I was just meaning for it to describe how IPCOP_shmat/shmat not being defined in the system causes the macro to be false so intercept_shmat/shmdt go undefined |
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Read related enhancement here: #7799 |
These op codes used to be in bits/ipc.h but were removed in glibc in 2015
with a comment saying they should be defined in internal headers:
https://sourceware.org/bugzilla/show_bug.cgi?id=18560
and when glibc uses that syscall it seems to do so from its own definitions:
https://github.com/bminor/glibc/search?q=IPCOP_shmat&unscoped_q=IPCOP_shmat
So I think using #ifndef and defining them if they're not already defined
using the values from glibc is the best option.
At IBM it was the testing on redhat 8 that found this as an issue
(the opcodes being undefined on the system made it select the
left undefined so shmat/shmdt memory events went unintercepted).
Signed-off-by: Mark Allen markalle@us.ibm.com