From mboxrd@z Thu Jan 1 00:00:00 1970 From: joern@purestorage.com (=?iso-8859-1?Q?J=F6rn?= Engel) Date: Tue, 8 Sep 2015 14:45:36 -0700 Subject: [Cocci] coccinelle problems with kernel code In-Reply-To: References: <20150908180759.GA27133@Sligo.logfs.org> Message-ID: <20150908214536.GC27133@Sligo.logfs.org> To: cocci@systeme.lip6.fr List-Id: cocci@systeme.lip6.fr On Tue, Sep 08, 2015 at 11:17:58PM +0200, Julia Lawall wrote: > On Tue, 8 Sep 2015, J?rn Engel wrote: > > > Tried to use coccinelle on the linux kernel for the first time. It > > seems to get things mostly right, but not quite. Here is the semantic > > patch: > > > > @@ expression E; @@ > > -down_read(&E->mmap_sem) > > +mm_read_lock(E) > > @@ expression E; @@ > > -down_read_trylock(&E->mmap_sem) > > +mm_read_trylock(E) > > @@ expression E; @@ > > -up_read(&E->mmap_sem) > > +mm_read_unlock(E) > > @@ expression E; @@ > > -down_write(&E->mmap_sem) > > +mm_write_lock(E) > > @@ expression E; @@ > > -down_write_trylock(&E->mmap_sem) > > +mm_write_trylock(E) > > @@ expression E; @@ > > -up_write(&E->mmap_sem) > > +mm_write_unlock(E) > > So this all went OK? Mostly. There are still a few troublemakers remaining. But few enough that I don't mind handling them manually. Automatic changes: 140 files changed, 581 insertions(+), 581 deletions(-) Troublemakers: arch/mips/mm/fault.c (5 lines) arch/um/include/asm/mmu_context.h (2 lines) include/linux/huge_mm.h (1 line) Commandline: spatch --sp-file mmap_sem.cocci --dir . --macro-file coccinelle.h If I explicitly pass the two headerfiles as parameters, they get handled as well. Maybe a bug in the recursive directory walk? arch/mips/mm/fault.c seems to have a problem with one of the conditionals. I could reduce things to the following testcase: void foo(unsigned long address) { down_read(&mm->mmap_sem); vma = find_vma(current->mm, address); if (!vma) goto bad_area; if (vma->vm_start <= address) goto good_area; if (!(vma->vm_flags & VM_GROWSDOWN)) goto bad_area; if (expand_stack(vma, address)) goto bad_area; bad_area: up_read(&mm->mmap_sem); } Remove the "!(vma->vm_flags & VM_GROWSDOWN)" condition and it works. Leave the condition and spatch fails silently. > > I run into problems whenever handling system calls. Looks like the > > SYSCALL_DEFINE5() macro and friends are causing problems. Here is my > > attempt to handle things. > > > > #define SYSCALL_DEFINE1(func, t1, a1) \ > > asmlinkage unsigned long func(t1 a1) > > #define SYSCALL_DEFINE2(func, t1, a1, t2, a2) \ > > asmlinkage unsigned long func(t1 a1, t2 a2) > > #define SYSCALL_DEFINE3(func, t1, a1, t2, a2, t3, a3) \ > > asmlinkage unsigned long func(t1 a1, t2 a2, t3 a3) > > #define SYSCALL_DEFINE4(func, t1, a1, t2, a2, t3, a3, t4, a4) \ > > asmlinkage unsigned long func(t1 a1, t2 a2, t3 a3, t4 a4) > > #define SYSCALL_DEFINE5(func, t1, a1, t2, a2, t3, a3, t4, a4, t5, a5) \ > > asmlinkage unsigned long func(t1 a1, t2 a2, t3 a3, t4 a4, t5 a5) > > #define SYSCALL_DEFINE6(func, t1, a1, t2, a2, t3, a3, t4, a4, t5, a5, t6, a6) \ > > asmlinkage unsigned long func(t1 a1, t2 a2, t3 a3, t4 a4, t5 a5, t6 a6) > > > > Should that be included into standard.h? > > If it works, I could certainly add it. It works. And tracking down failures in coccinelle is definitely more fun than making 581 manual changes without messing things up. Thank you! J?rn -- Homo Sapiens is a goal, not a description. -- unknown