From c132aa450391f0b77ce281e42aa4d97b4682d8f2 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Thu, 31 Aug 2017 09:14:09 +0200 Subject: [PATCH] 4.9-stable patches added patches: lz4-fix-bogus-gcc-warning.patch --- queue-4.9/lz4-fix-bogus-gcc-warning.patch | 48 +++++++++++++++++++++++ queue-4.9/series | 1 + 2 files changed, 49 insertions(+) create mode 100644 queue-4.9/lz4-fix-bogus-gcc-warning.patch diff --git a/queue-4.9/lz4-fix-bogus-gcc-warning.patch b/queue-4.9/lz4-fix-bogus-gcc-warning.patch new file mode 100644 index 00000000000..446501f376c --- /dev/null +++ b/queue-4.9/lz4-fix-bogus-gcc-warning.patch @@ -0,0 +1,48 @@ +From foo@baz Thu Aug 31 09:09:54 CEST 2017 +Date: Thu, 31 Aug 2017 09:09:54 +0200 +To: Greg KH +From: Greg Kroah-Hartman +Subject: lz4: fix bogus gcc warning + +From: Greg Kroah-Hartman + +When building lz4 under gcc-7 we get the following bogus warning: + + CC [M] lib/lz4/lz4hc_compress.o +lib/lz4/lz4hc_compress.c: In function ‘lz4hc_compress’: +lib/lz4/lz4hc_compress.c:179:42: warning: ‘delta’ may be used uninitialized in this function [-Wmaybe-uninitialized] + chaintable[(size_t)(ptr) & MAXD_MASK] = delta; + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~ +lib/lz4/lz4hc_compress.c:134:6: note: ‘delta’ was declared here + u16 delta; + ^~~~~ + +This doesn't show up in the 4.4-stable tree due to us turning off +warnings like this. It also doesn't show up in newer kernel versions as +this code was totally rewritten. + +So for now, to get the 4.9-stable tree to build with 0 warnings on x86 +allmodconfig, let's just shut the compiler up by initializing the +variable to 0, despite it not really doing anything. + +To be far, this code is crazy complex, so the fact that gcc can't +determine if the variable is really used or not isn't that bad, I'd +blame the code here instead of the compiler. + +Signed-off-by: Greg Kroah-Hartman + +--- + lib/lz4/lz4hc_compress.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/lib/lz4/lz4hc_compress.c ++++ b/lib/lz4/lz4hc_compress.c +@@ -131,7 +131,7 @@ static inline int lz4hc_insertandfindbes + #endif + int nbattempts = MAX_NB_ATTEMPTS; + size_t repl = 0, ml = 0; +- u16 delta; ++ u16 delta = 0; + + /* HC4 match finder */ + lz4hc_insert(hc4, ip); diff --git a/queue-4.9/series b/queue-4.9/series index 7f1c743271a..eef2fa70d48 100644 --- a/queue-4.9/series +++ b/queue-4.9/series @@ -9,3 +9,4 @@ arm64-fpsimd-prevent-registers-leaking-across-exec.patch locking-spinlock-debug-remove-spinlock-lockup-detection-code.patch scsi-sg-protect-accesses-to-reserved-page-array.patch scsi-sg-reset-res_in_use-after-unlinking-reserved-array.patch +lz4-fix-bogus-gcc-warning.patch -- 2.47.3