Message-ID: <20220919101523.043382530@infradead.org>
Date:   Mon, 19 Sep 2022 12:00:19 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     peterz@...radead.org
Cc:     richard.henderson@...aro.org, ink@...assic.park.msu.ru,
        mattst88@...il.com, vgupta@...nel.org, linux@...linux.org.uk,
        ulli.kroll@...glemail.com, linus.walleij@...aro.org,
        shawnguo@...nel.org, Sascha Hauer <s.hauer@...gutronix.de>,
        kernel@...gutronix.de, festevam@...il.com, linux-imx@....com,
        tony@...mide.com, khilman@...nel.org, catalin.marinas@....com,
        will@...nel.org, guoren@...nel.org, bcain@...cinc.com,
        chenhuacai@...nel.org, kernel@...0n.name, geert@...ux-m68k.org,
        sammy@...my.net, monstr@...str.eu, tsbogend@...ha.franken.de,
        dinguyen@...nel.org, jonas@...thpole.se,
        stefan.kristiansson@...nalahti.fi, shorne@...il.com,
        James.Bottomley@...senPartnership.com, deller@....de,
        mpe@...erman.id.au, npiggin@...il.com, christophe.leroy@...roup.eu,
        paul.walmsley@...ive.com, palmer@...belt.com,
        aou@...s.berkeley.edu, hca@...ux.ibm.com, gor@...ux.ibm.com,
        agordeev@...ux.ibm.com, borntraeger@...ux.ibm.com,
        svens@...ux.ibm.com, ysato@...rs.sourceforge.jp, dalias@...c.org,
        davem@...emloft.net, richard@....at,
        anton.ivanov@...bridgegreys.com, johannes@...solutions.net,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com, x86@...nel.org, hpa@...or.com,
        acme@...nel.org, mark.rutland@....com,
        alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
        namhyung@...nel.org, jgross@...e.com, srivatsa@...il.mit.edu,
        amakhalov@...are.com, pv-drivers@...are.com,
        boris.ostrovsky@...cle.com, chris@...kel.net, jcmvbkbc@...il.com,
        rafael@...nel.org, lenb@...nel.org, pavel@....cz,
        gregkh@...uxfoundation.org, mturquette@...libre.com,
        sboyd@...nel.org, daniel.lezcano@...aro.org, lpieralisi@...nel.org,
        sudeep.holla@....com, agross@...nel.org,
        bjorn.andersson@...aro.org, konrad.dybcio@...ainline.org,
        anup@...infault.org, thierry.reding@...il.com,
        jonathanh@...dia.com, jacob.jun.pan@...ux.intel.com,
        atishp@...shpatra.org, Arnd Bergmann <arnd@...db.de>,
        yury.norov@...il.com, andriy.shevchenko@...ux.intel.com,
        linux@...musvillemoes.dk, dennis@...nel.org, tj@...nel.org,
        cl@...ux.com, rostedt@...dmis.org, pmladek@...e.com,
        senozhatsky@...omium.org, john.ogness@...utronix.de,
        juri.lelli@...hat.com, vincent.guittot@...aro.org,
        dietmar.eggemann@....com, bsegall@...gle.com, mgorman@...e.de,
        bristot@...hat.com, vschneid@...hat.com, fweisbec@...il.com,
        ryabinin.a.a@...il.com, glider@...gle.com, andreyknvl@...il.com,
        dvyukov@...gle.com, vincenzo.frascino@....com,
        Andrew Morton <akpm@...ux-foundation.org>, jpoimboe@...nel.org,
        linux-alpha@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-snps-arc@...ts.infradead.org, linux-omap@...r.kernel.org,
        linux-csky@...r.kernel.org, linux-hexagon@...r.kernel.org,
        linux-ia64@...r.kernel.org, loongarch@...ts.linux.dev,
        linux-m68k@...ts.linux-m68k.org, linux-mips@...r.kernel.org,
        openrisc@...ts.librecores.org, linux-parisc@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, linux-riscv@...ts.infradead.org,
        linux-s390@...r.kernel.org, linux-sh@...r.kernel.org,
        sparclinux@...r.kernel.org, linux-um@...ts.infradead.org,
        linux-perf-users@...r.kernel.org,
        virtualization@...ts.linux-foundation.org,
        linux-xtensa@...ux-xtensa.org, linux-acpi@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-arch@...r.kernel.org, kasan-dev@...glegroups.com
Subject: [PATCH v2 40/44] ubsan: Fix objtool UACCESS warns

clang-14 allyesconfig gives:

vmlinux.o: warning: objtool: emulator_cmpxchg_emulated+0x705: call to __ubsan_handle_load_invalid_value() with UACCESS enabled
vmlinux.o: warning: objtool: paging64_update_accessed_dirty_bits+0x39e: call to __ubsan_handle_load_invalid_value() with UACCESS enabled
vmlinux.o: warning: objtool: paging32_update_accessed_dirty_bits+0x390: call to __ubsan_handle_load_invalid_value() with UACCESS enabled
vmlinux.o: warning: objtool: ept_update_accessed_dirty_bits+0x43f: call to __ubsan_handle_load_invalid_value() with UACCESS enabled

Add the required eflags save/restore and whitelist the thing.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 lib/ubsan.c           |    5 ++++-
 tools/objtool/check.c |    1 +
 2 files changed, 5 insertions(+), 1 deletion(-)

--- a/lib/ubsan.c
+++ b/lib/ubsan.c
@@ -340,9 +340,10 @@ void __ubsan_handle_load_invalid_value(v
 {
 	struct invalid_value_data *data = _data;
 	char val_str[VALUE_LENGTH];
+	unsigned long ua_flags = user_access_save();
 
 	if (suppress_report(&data->location))
-		return;
+		goto out;
 
 	ubsan_prologue(&data->location, "invalid-load");
 
@@ -352,6 +353,8 @@ void __ubsan_handle_load_invalid_value(v
 		val_str, data->type->type_name);
 
 	ubsan_epilogue();
+out:
+	user_access_restore(ua_flags);
 }
 EXPORT_SYMBOL(__ubsan_handle_load_invalid_value);
 
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1068,6 +1068,7 @@ static const char *uaccess_safe_builtin[
 	"__ubsan_handle_type_mismatch",
 	"__ubsan_handle_type_mismatch_v1",
 	"__ubsan_handle_shift_out_of_bounds",
+	"__ubsan_handle_load_invalid_value",
 	/* misc */
 	"csum_partial_copy_generic",
 	"copy_mc_fragile",

Powered by blists - more mailing lists