libdrgn: prepare for libkdumpfile-0.5.5 #452
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Since libkdumpfile commit 5b044292abe9 ("Clarify and fix attribute data
lifetime") changes the lifetime of attribute values retrieved with
kdump_attr_ref_get(), the extra reference would keep the PRSTATUS blob
around even after kdump_free().
However, the attribute hierarchy cannot change while iterating over the
PRSTATUS attributes, so it is not necessary to take an attribute reference
and we can use kdump_get_typed_attr().
The attribute blob itself should not change either, but it is a good idea
to keep its data pinned, because a raw pointer to it is stored in the
drgn_thread_set hash table. If some code tries to modify the PRSTATUS
attribute data, the attempt will fail with KDUMP_ERR_BUSY rather than leave
a dangling pointer in the hash table and possibly cause a UAF bug later.
The blob pin does not prevent freeing the blob when the blob reference
count reaches zero.
Signed-off-by: Petr Tesarik <[email protected]>
The kdump_get_typed_attr() function prototype changed in libkdumpfile
commit e182aeaf4d72 ("Make kdump_get_typed_attr() easier to use").
Signed-off-by: Petr Tesarik <[email protected]>
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Thanks! I was only able to test 0.5.4, but I'm taking your word for it on the upcoming 0.5.5. |
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Adapt to libkdumpfile attribute lifetime fixes.