Segfault in libopenblas0-pthread

[Sébastien Villemot]

Hi Diego,

Le mercredi 13 octobre 2021 à 07:56 +0200, difa.csi a écrit :
> Following quite a bit of debugging, I think I've found a wrong check in 
> memory.c file, at line 2789 (0.3.13+ds-3):
> https://sources.debian.org/src/openblas/0.3.13+ds-3/driver/others/memory.c/
> 
> IIUC, it should check *func != NULL instead of func != NULL . func 
> should be "guaranteed" to not be NULL since memoryalloc is defined at 
> line 2641.
> 
> Else, when it reaches the last element of memoryalloc[], func is not 
> NULL but *func is, and it's what gets dereferenced.
> 
> I noticed it because both octave and python-numpy started segfaulting 
> after a distro upgrade.
> In both cases the stack trace contained something like:
> #0  0x0000000000000000 in ?? ()
> #1  0x00007f9c614de7d9 in ?? () from 
> /usr/lib/x86_64-linux-gnu/libopenblas.so.0
> 
> and valgrind trace:
> ==746909== Jump to the invalid address stated on the next line
> ==746909==    at 0x0: ???
> ==746909==    by 0xBDFD708: blas_memory_alloc (memory.c:2793)
> ==746909==    by 0xBDFDF03: blas_thread_server (blas_server.c:366)
> ==746909==    by 0x8D33EA6: start_thread (pthread_create.c:477)
> ==746909==    by 0x725EDEE: clone (clone.S:95)
> ==746909==  Address 0x0 is not stack'd, malloc'd or (recently) free'd
> 
> Strangely, the segfaults disappeared installing libopenblas0-serial.

I guess you did that debugging in relation to #995450.

I suggest that you communicate your above analysis directly to
upstream, by opening an issue at:
https://github.com/xianyi/OpenBLAS/issues/new

The upstream developers are in the best position to give you feedback
and to decide whether or not to apply your suggested patch.

Best,

-- 
⢀⣴⠾⠻⢶⣦⠀  Sébastien Villemot
⣾⠁⢠⠒⠀⣿⡁  Debian Developer
⢿⡄⠘⠷⠚⠋⠀  https://sebastien.villemot.name
⠈⠳⣄⠀⠀⠀⠀  https://www.debian.org

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