> FYI - I'm a tiny bit taken aback that in response to me applying, > and providing feedback, on your patch,
This will probably trigger collateral evolution, won't it? > you respond with 2 links for me to follow I offered another bit of background information according to your enquiry. > and cut off a chunk of my feedback. Will this part become relevant for a subsequent patch? > Seems like it would taken the same amount of time to just answer my > two questions directly. Do you find linked information sources also helpful? > Was this part of a larger patch set? Not for this software module. But one of my scripts for the semantic patch language pointed several update candidates out. Thus I sent 19 patches according to these change possibilities so far. (Would you become interested to take another look by the means of mailing list archives?) > Andy's comment seems to indicate that. Andy Shevchenko was informed because he is involved also in the evolution of other components. >>> What is the risk of undefined behavior? >> >> See also: >> https://wiki.sei.cmu.edu/confluence/display/c/EXP34-C.+Do+not+dereference+null+pointers?focusedCommentId=405504137#comment-405504137 > > Where is the NULL pointer dereference here? I hope that you can become more aware that access attempts for data structure members (also by using the arrow operator) can occasionally be problematic before null pointer checks. >>>> This issue was detected by using the Coccinelle software. >>> Which cocci script? >> >> See also: >> Reconsidering pointer dereferences before null pointer checks (with SmPL) >> https://lore.kernel.org/cocci/1a11455f-ab57-dce0-1677-6beb8492a...@web.de/ >> https://sympa.inria.fr/sympa/arc/cocci/2023-04/msg00021.html > > The cocci script linked above does not seem to apply here. Which command did you try out? Do you find the following data processing result reasonable? Markus_Elfring@Sonne:…/Projekte/Linux/next-analyses> spatch …/Projekte/Coccinelle/janitor/show_pointer_dereferences_before_check7.cocci drivers/nvdimm/pfn_devs.c … @@ -456,9 +456,7 @@ int nd_pfn_validate(struct nd_pfn *nd_pf unsigned long align, start_pad; struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb; struct nd_namespace_common *ndns = nd_pfn->ndns; - const uuid_t *parent_uuid = nd_dev_to_uuid(&ndns->dev); - if (!pfn_sb || !ndns) return -ENODEV; if (!is_memory(nd_pfn->dev.parent)) Regards, Markus
