Re: [Cocci] Checking for a null pointer with SmPL
>> Can the mentioned SmPL script variant work also without taking extra >> software transformations by isomorphism specifications into account? > > Well, you already know that it doesn't. So oviously the answe is that it > cannot. At the moment. > If you indicate that the expression ex is a pointer then maybe it will work. Should the available data type information be sufficient for the handling of pointers in the discussed use case? Example: struct setkey_parm *psetkeyparm; Regards, Markus ___ Cocci mailing list Cocci@systeme.lip6.fr https://systeme.lip6.fr/mailman/listinfo/cocci
Re: [Cocci] Checking for a null pointer with SmPL
> Isomorphisms happen in advance, not during the matching process. Can the mentioned SmPL script variant work also without taking extra software transformations by isomorphism specifications into account? Regards, Markus ___ Cocci mailing list Cocci@systeme.lip6.fr https://systeme.lip6.fr/mailman/listinfo/cocci
Re: [Cocci] Checking for a null pointer with SmPL
On Mon, 17 Jun 2019, Markus Elfring wrote: > >> Should an isomorphism specification like “not_ptr2” help here? > >> https://github.com/coccinelle/coccinelle/blob/19ee1697bf152d37a78a20cefe148775bf4b0e0d/standard.iso#L157 > > > > No, because Coccinelle does not know that it is a pointer. > > How should it know? > > Can the software determine that the expression metavariable refers to > a pointer variable (within the implementation of a function like > “rtw_ap_set_key”)? > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/staging/rtl8723bs/core/rtw_ap.c?id=9e0babf2c06c73cda2c0cd37a1653d823adb40ec#n1479 > https://elixir.bootlin.com/linux/v5.2-rc5/source/drivers/staging/rtl8723bs/core/rtw_ap.c#L1479 Isomorphisms happen in advance, not during the matching process. julia___ Cocci mailing list Cocci@systeme.lip6.fr https://systeme.lip6.fr/mailman/listinfo/cocci
Re: [Cocci] Checking for a null pointer with SmPL
>> Should an isomorphism specification like “not_ptr2” help here? >> https://github.com/coccinelle/coccinelle/blob/19ee1697bf152d37a78a20cefe148775bf4b0e0d/standard.iso#L157 > > No, because Coccinelle does not know that it is a pointer. > How should it know? Can the software determine that the expression metavariable refers to a pointer variable (within the implementation of a function like “rtw_ap_set_key”)? https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/staging/rtl8723bs/core/rtw_ap.c?id=9e0babf2c06c73cda2c0cd37a1653d823adb40ec#n1479 https://elixir.bootlin.com/linux/v5.2-rc5/source/drivers/staging/rtl8723bs/core/rtw_ap.c#L1479 Regards, Markus ___ Cocci mailing list Cocci@systeme.lip6.fr https://systeme.lip6.fr/mailman/listinfo/cocci
Re: [Cocci] Checking for a null pointer with SmPL
> In the second case, Coccinelle has no way of knowing that ex is a pointer, Can the software support pointer expressions better? > so it doesn't feel motivated to consider that ex should be compared to NULL. Should an isomorphism specification like “not_ptr2” help here? https://github.com/coccinelle/coccinelle/blob/19ee1697bf152d37a78a20cefe148775bf4b0e0d/standard.iso#L157 > I would imagine that you would have gooten at least some relevant > information if you had tried spatch --parse-cocci. This data display can give useful hints. Are we waiting also for a more complete software documentation in such an application area? Regards, Markus ___ Cocci mailing list Cocci@systeme.lip6.fr https://systeme.lip6.fr/mailman/listinfo/cocci
Re: [Cocci] Checking for a null pointer with SmPL
On Sun, 16 Jun 2019, Markus Elfring wrote: > Hello, > > A patch on a topic like “staging/rtl8723bs/core/rtw_ap: Remove redundant call > to memset” caught also my software development attention. > https://lkml.org/lkml/2019/6/15/220 > https://lore.kernel.org/patchwork/patch/1089416/ > https://lore.kernel.org/lkml/20190616033527.GA14062@hari-Inspiron-1545/ > > > The following script for the semantic patch language points the shown > change possibility out as expected. > > @display@ > expression ex; > identifier zm =~ "_zmalloc"; > statement is; > @@ > ex = zm(...); > if (ex == NULL) > is > > *memset(ex, 0, ...); > > > > I would expect that the following SmPL script can work in a similar way. > > @display@ > expression ex; > identifier zm =~ "_zmalloc"; > statement is, es; > @@ > ex = zm(...); > if (ex) > is > else > es > > *memset(ex, 0, ...); > > > But this approach does not point an update candidate out at the moment. > How do you think about the software situation? In the second case, Coccinelle has no way of knowing that ex is a pointer, so it doesn't feel motivated to consider that ex should be compared to NULL. I would imagine that you would have gooten at least some relevant information if you had tried spatch --parse-cocci. julia___ Cocci mailing list Cocci@systeme.lip6.fr https://systeme.lip6.fr/mailman/listinfo/cocci
[Cocci] Checking for a null pointer with SmPL
Hello, A patch on a topic like “staging/rtl8723bs/core/rtw_ap: Remove redundant call to memset” caught also my software development attention. https://lkml.org/lkml/2019/6/15/220 https://lore.kernel.org/patchwork/patch/1089416/ https://lore.kernel.org/lkml/20190616033527.GA14062@hari-Inspiron-1545/ The following script for the semantic patch language points the shown change possibility out as expected. @display@ expression ex; identifier zm =~ "_zmalloc"; statement is; @@ ex = zm(...); if (ex == NULL) is *memset(ex, 0, ...); I would expect that the following SmPL script can work in a similar way. @display@ expression ex; identifier zm =~ "_zmalloc"; statement is, es; @@ ex = zm(...); if (ex) is else es *memset(ex, 0, ...); But this approach does not point an update candidate out at the moment. How do you think about the software situation? Regards, Markus ___ Cocci mailing list Cocci@systeme.lip6.fr https://systeme.lip6.fr/mailman/listinfo/cocci
