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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mark-PK Tsai <mark-pk.tsai@mediatek.com>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>
Subject: [for-linus][PATCH 1/4] recordmcount: Correct st_shndx handling
Date: Fri, 18 Jun 2021 09:20:47 -0400	[thread overview]
Message-ID: <20210618132125.614067272@goodmis.org> (raw)
In-Reply-To: 20210618132046.600413369@goodmis.org

From: Peter Zijlstra <peterz@infradead.org>

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.

Link: https://lore.kernel.org/lkml/20210607023839.26387-1-mark-pk.tsai@mediatek.com/
Link: https://lkml.kernel.org/r/20210616154126.2794-1-mark-pk.tsai@mediatek.com

Reported-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Tested-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
[handle endianness of sym->st_shndx]
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 scripts/recordmcount.h | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
index f9b19524da11..1e9baa5c4fc6 100644
--- a/scripts/recordmcount.h
+++ b/scripts/recordmcount.h
@@ -192,15 +192,20 @@ static unsigned int get_symindex(Elf_Sym const *sym, Elf32_Word const *symtab,
 				 Elf32_Word const *symtab_shndx)
 {
 	unsigned long offset;
+	unsigned short shndx = w2(sym->st_shndx);
 	int index;
 
-	if (sym->st_shndx != SHN_XINDEX)
-		return w2(sym->st_shndx);
+	if (shndx > SHN_UNDEF && shndx < SHN_LORESERVE)
+		return shndx;
 
-	offset = (unsigned long)sym - (unsigned long)symtab;
-	index = offset / sizeof(*sym);
+	if (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)
-- 
2.30.2

  reply	other threads:[~2021-06-18 13:21 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-18 13:20 [for-linus][PATCH 0/4] tracing: Some fixes for 5.13 Steven Rostedt
2021-06-18 13:20 ` Steven Rostedt [this message]
2021-06-18 13:20 ` [for-linus][PATCH 2/4] tracing: Do not stop recording cmdlines when tracing is off Steven Rostedt
2021-06-18 13:20 ` [for-linus][PATCH 3/4] tracing: Do not stop recording comms if the trace file is being read Steven Rostedt
2021-06-18 13:20 ` [for-linus][PATCH 4/4] tracing: Do no increment trace_clock_global() by one Steven Rostedt

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