2021-06-15 06:48:22

by Mark-PK Tsai

Subject: [PATCH v2] recordmcount: Correct st_shndx handling

One should only use st_shndx when >SHN_UNDEF and <SHN_LORESERVE. When
SHN_XINDEX, then use .symtab_shndx. Otherwise use 0.

This handles the case: st_shndx >= SHN_LORESERVE && st_shndx != SHN_XINDEX.

Reported-by: Mark-PK Tsai <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Tested-by: Mark-PK Tsai <[email protected]>
Signed-off-by: Mark-PK Tsai <[email protected]>
---
scripts/recordmcount.h | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
index f9b19524da11..ef9c3425f86b 100644
--- a/scripts/recordmcount.h
+++ b/scripts/recordmcount.h
@@ -194,13 +194,18 @@ static unsigned int get_symindex(Elf_Sym const *sym, Elf32_Word const *symtab,
unsigned long offset;
int index;

- if (sym->st_shndx != SHN_XINDEX)
+ if (w2(sym->st_shndx) > SHN_UNDEF &&
+ w2(sym->st_shndx) < SHN_LORESERVE)
return w2(sym->st_shndx);

- offset = (unsigned long)sym - (unsigned long)symtab;
- index = offset / sizeof(*sym);
+ if (w2(sym->st_shndx) == SHN_XINDEX) {
+ offset = (unsigned long)sym - (unsigned long)symtab;
+ index = offset / sizeof(*sym);

- return w(symtab_shndx[index]);
+ return w(symtab_shndx[index]);
+ }
+
+ return 0;
}

static unsigned int get_shnum(Elf_Ehdr const *ehdr, Elf_Shdr const *shdr0)
--
2.18.0

2021-06-15 15:44:02

by Steven Rostedt

Subject: Re: [PATCH v2] recordmcount: Correct st_shndx handling

On Tue, 15 Jun 2021 14:47:20 +0800
Mark-PK Tsai <[email protected]> wrote:

> One should only use st_shndx when >SHN_UNDEF and <SHN_LORESERVE. When
> SHN_XINDEX, then use .symtab_shndx. Otherwise use 0.
>
> This handles the case: st_shndx >= SHN_LORESERVE && st_shndx != SHN_XINDEX.
>
> Reported-by: Mark-PK Tsai <[email protected]>
> Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
> Tested-by: Mark-PK Tsai <[email protected]>
> Signed-off-by: Mark-PK Tsai <[email protected]>

Please explain the two signed-off-by's above. If you are just tweaking
Peter's original patch, please add at the start:

From: Peter Zijlstra (Intel) <[email protected]>

And then just above your signed off by, add what you changed:

Tested-by: Mark-PK Tsai <[email protected]>
[ Changed something ]
Signed-off-by: Mark-PK Tsai <[email protected]>

But state what you changed.

Thanks!

-- Steve

2021-06-15 16:35:20

by Mark-PK Tsai

Subject: Re: [PATCH v2] recordmcount: Correct st_shndx handling

> On Tue, 15 Jun 2021 14:47:20 +0800
> Mark-PK Tsai <[email protected]> wrote:
>
> > One should only use st_shndx when >SHN_UNDEF and <SHN_LORESERVE. When
> > SHN_XINDEX, then use .symtab_shndx. Otherwise use 0.
> >
> > This handles the case: st_shndx >= SHN_LORESERVE && st_shndx != SHN_XINDEX.
> >
> > Reported-by: Mark-PK Tsai <[email protected]>
> > Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
> > Tested-by: Mark-PK Tsai <[email protected]>
> > Signed-off-by: Mark-PK Tsai <[email protected]>
>
> Please explain the two signed-off-by's above. If you are just tweaking
> Peter's original patch, please add at the start:
>
> From: Peter Zijlstra (Intel) <[email protected]>
>
> And then just above your signed off by, add what you changed:
>
> Tested-by: Mark-PK Tsai <[email protected]>
> [ Changed something ]
> Signed-off-by: Mark-PK Tsai <[email protected]>
>
> But state what you changed.
>
> Thanks!
>
> -- Steve

Sorry for messing up.
I've fixed it in v3.

Thanks for your comment.

2021-06-15 17:08:24

by Steven Rostedt

Subject: Re: [PATCH v2] recordmcount: Correct st_shndx handling

On Wed, 16 Jun 2021 00:32:45 +0800
Mark-PK Tsai <[email protected]> wrote:

> > On Tue, 15 Jun 2021 14:47:20 +0800
> > Mark-PK Tsai <[email protected]> wrote:
> >
> > > One should only use st_shndx when >SHN_UNDEF and <SHN_LORESERVE. When
> > > SHN_XINDEX, then use .symtab_shndx. Otherwise use 0.
> > >
> > > This handles the case: st_shndx >= SHN_LORESERVE && st_shndx != SHN_XINDEX.
> > >
> > > Reported-by: Mark-PK Tsai <[email protected]>
> > > Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
> > > Tested-by: Mark-PK Tsai <[email protected]>
> > > Signed-off-by: Mark-PK Tsai <[email protected]>
> >
> > Please explain the two signed-off-by's above. If you are just tweaking
> > Peter's original patch, please add at the start:
> >
> > From: Peter Zijlstra (Intel) <[email protected]>
> >
> > And then just above your signed off by, add what you changed:
> >
> > Tested-by: Mark-PK Tsai <[email protected]>
> > [ Changed something ]
> > Signed-off-by: Mark-PK Tsai <[email protected]>
> >
> > But state what you changed.
> >
> > Thanks!
> >
> > -- Steve
>
> Sorry for messing up.

No problem. It's a learning process.

> I've fixed it in v3.

Thanks,

-- Steve