The branch main has been updated by arichardson:
URL:
https://cgit.FreeBSD.org/src/commit/?id=9efbe526e00f47d946b3320f595e73fea26805df
commit 9efbe526e00f47d946b3320f595e73fea26805df
Author: Alex Richardson <arichard...@freebsd.org>
AuthorDate: 2021-08-02 08:49:21 +0000
Commit: Alex Richardson <arichard...@freebsd.org>
CommitDate: 2021-08-02 13:33:24 +0000
libthr: work around an ASAN false-positive
I got the following error with an ASAN-instrument libthr:
==803==ERROR: AddressSanitizer: stack-buffer-overflow on address
0x7fffffffcdb0 at pc 0x000801863396 bp 0x7ff8
READ of size 4 at 0x7fffffffcdb0 thread T0
#0 0x801863395 in handle_signal
/local/scratch/alr48/cheri/freebsd/lib/libthr/thread/thr_sig.c:262:2
#1 0x801860da2 in thr_sighandler
/local/scratch/alr48/cheri/freebsd/lib/libthr/thread/thr_sig.c:246:2
Address 0x7fffffffcdb0 is located in stack of thread T0 at offset 208 in
frame
#0 0x80186080f in thr_sighandler
/local/scratch/alr48/cheri/freebsd/lib/libthr/thread/thr_sig.c:213
This frame has 1 object(s):
[32, 64) 'act' (line 216) <== Memory access at offset 208 overflows
this variable
HINT: this may be a false positive if your program uses some custom stack
This seems like a false-positive since the line in question is
`SIGSETOR(actp->sa_mask, ucp->uc_sigmask);` and it complains about a read
operation (from the ucontext_t argument) so this indicates to me that ASAN
does not understand that thr_sighandler() is a signal handler.
Differential Revision: https://reviews.freebsd.org/D31074
---
lib/libthr/Makefile | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/lib/libthr/Makefile b/lib/libthr/Makefile
index 1a5dfa18dca7..038823413cb2 100644
--- a/lib/libthr/Makefile
+++ b/lib/libthr/Makefile
@@ -29,6 +29,12 @@ CFLAGS+=-I${SRCTOP}/lib/libthread_db
CFLAGS.thr_stack.c+= -Wno-cast-align
CFLAGS.rtld_malloc.c+= -Wno-cast-align
CFLAGS.thr_symbols.c+= -Wno-missing-variable-declarations
+.if ${MK_ASAN} != "no"
+# False-positive ASAN error claiming the local "struct sigaction act;" is
+# overflowed by handle_signal() reading from the ucontext_t argument. This
+# could be caused by ASAN not treating this function as a signal handler.
+CFLAGS.thr_sig.c+= -fno-sanitize=address
+.endif
.ifndef NO_THREAD_UNWIND_STACK
CFLAGS+=-fexceptions
_______________________________________________
dev-commits-src-main@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/dev-commits-src-main
To unsubscribe, send any mail to "dev-commits-src-main-unsubscr...@freebsd.org"
