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David Rientjes authored
u32_array_open() is racy when multiple threads read from a file with a seek position of zero, i.e. when two or more simultaneous reads are occurring after the non-seekable files are created. It is possible that file->private_data is double-freed because the threads races between kfree(file->private-data); and file->private_data = NULL; The fix is to only do format_array_alloc() when the file is opened and free it when it is closed. Note that because the file has always been non-seekable, you can't open it and read it multiple times anyway, so the data has always been generated just once. The difference is that now it is generated at open time rather than at the time of the first read, and that avoids the race. Reported-by:
Dave Jones <davej@redhat.com> Acked-by:
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Tested-by:
Raghavendra <raghavendra.kt@linux.vnet.ibm.com> Signed-off-by:
David Rientjes <rientjes@google.com> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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