Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Date | Thu, 8 Aug 2019 22:45:34 +0200 | Subject | Re: [arnd-playground:randconfig-5.3-rc2 32/347] fs/reiserfs/prints.o: warning: objtool: __reiserfs_error()+0x80: unreachable instruction |
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On Thu, Aug 8, 2019 at 9:06 PM kbuild test robot <lkp@intel.com> wrote: > > tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/arnd/playground.git randconfig-5.3-rc2 > head: bfe9aede7372c8310a9bf31963460c9dd11d1f82 > commit: 97919a3ec80e9841c4bbac14a80e8b9d482666d4 [32/347] [SUBMITTED 20190718] reiserfs: fix code unwinding with clang > config: x86_64-lkp (attached as .config) > compiler: gcc-7 (Debian 7.4.0-10) 7.4.0 > reproduce: > git checkout 97919a3ec80e9841c4bbac14a80e8b9d482666d4 > # save the attached .config to linux build tree > make ARCH=x86_64 > > If you fix the issue, kindly add following tag > Reported-by: kbuild test robot <lkp@intel.com> > > All warnings (new ones prefixed by >>): > > >> fs/reiserfs/namei.o: warning: objtool: entry_points_to_object()+0x117: unreachable instruction > -- > >> fs/reiserfs/do_balan.o: warning: objtool: get_FEB()+0x55: unreachable instruction > >> fs/reiserfs/prints.o: warning: objtool: __reiserfs_error()+0x80: unreachable instruction > >> fs/reiserfs/lbalance.o: warning: objtool: leaf_move_items()+0x210: unreachable instruction > >> fs/reiserfs/fix_node.o: warning: objtool: create_virtual_node()+0x295: unreachable instruction > >> fs/reiserfs/inode.o: warning: objtool: reiserfs_update_sd_size()+0x26b: unreachable instruction > >> fs/reiserfs/ibalance.o: warning: objtool: balance_internal()+0x30d: unreachable instruction > >> fs/reiserfs/stree.o: warning: objtool: reiserfs_cut_from_item()+0x239: unreachable instruction > >> fs/reiserfs/tail_conversion.o: warning: objtool: direct2indirect()+0x29c: unreachable instruction > >> fs/reiserfs/item_ops.o: warning: objtool: direntry_check_left()+0x5d: unreachable instruction > >> fs/reiserfs/journal.o: warning: objtool: flush_commit_list()+0x552: unreachable instruction
Great fun. The patch I did was my workaround for a related problem with clang, see below.
Josh, is this warning above something you are interested in? I don't think it happens in mainline, but it could happen anywhere. I think the patch below can be dropped once clang is fixed, but I have so far been unable to build a new compiler for testing.
Arnd
commit 97919a3ec80e9841c4bbac14a80e8b9d482666d4 Author: Arnd Bergmann <arnd@arndb.de> Date: Fri Jul 12 16:19:52 2019 +0200
[SUBMITTED 20190718] reiserfs: fix code unwinding with clang
Building reiserfs with clang leads to objtool warnings about a part of the unreachable code that may confuse the ORC unwinder:
fs/reiserfs/ibalance.o: warning: objtool: balance_internal()+0xe8f: stack state mismatch: cfa1=7+240 cfa2=7+248 fs/reiserfs/ibalance.o: warning: objtool: internal_move_pointers_items()+0x36f: stack state mismatch: cfa1=7+152 cfa2=7+144 fs/reiserfs/lbalance.o: warning: objtool: leaf_cut_from_buffer()+0x58b: stack state mismatch: cfa1=7+128 cfa2=7+112 fs/reiserfs/lbalance.o: warning: objtool: leaf_copy_boundary_item()+0x7a9: stack state mismatch: cfa1=7+104 cfa2=7+96 fs/reiserfs/lbalance.o: warning: objtool: leaf_copy_items_entirely()+0x3d2: stack state mismatch: cfa1=7+120 cfa2=7+128 fs/reiserfs/do_balan.o: warning: objtool: replace_key()+0x158: stack state mismatch: cfa1=7+40 cfa2=7+56 fs/reiserfs/do_balan.o: warning: objtool: balance_leaf()+0x2791: stack state mismatch: cfa1=7+176 cfa2=7+192
Reword this to use the regular BUG() call directly from the original code location, since objtool finds the generated object code more reasonable.
This will likely get fixed in a future clang release, but in the meantime the workaround helps us build cleanly with existing releases.
Link: https://groups.google.com/d/msgid/clang-built-linux/20190712135755.7qa4wxw3bfmwn5rp%40treble Signed-off-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/fs/reiserfs/prints.c b/fs/reiserfs/prints.c index 9fed1c05f1f4..da996eaaebac 100644 --- a/fs/reiserfs/prints.c +++ b/fs/reiserfs/prints.c @@ -387,7 +387,6 @@ void __reiserfs_panic(struct super_block *sb, const char *id, else printk(KERN_WARNING "REISERFS panic: %s%s%s: %s\n", id ? id : "", id ? " " : "", function, error_buf); - BUG(); }
void __reiserfs_error(struct super_block *sb, const char *id, @@ -397,8 +396,10 @@ void __reiserfs_error(struct super_block *sb, const char *id,
BUG_ON(sb == NULL);
- if (reiserfs_error_panic(sb)) + if (reiserfs_error_panic(sb)) { __reiserfs_panic(sb, id, function, error_buf); + BUG(); + }
if (id && id[0]) printk(KERN_CRIT "REISERFS error (device %s): %s %s: %s\n", diff --git a/fs/reiserfs/reiserfs.h b/fs/reiserfs/reiserfs.h index e5ca9ed79e54..f5bd17ee21f6 100644 --- a/fs/reiserfs/reiserfs.h +++ b/fs/reiserfs/reiserfs.h @@ -3185,10 +3185,9 @@ void unfix_nodes(struct tree_balance *);
/* prints.c */ void __reiserfs_panic(struct super_block *s, const char *id, - const char *function, const char *fmt, ...) - __attribute__ ((noreturn)); + const char *function, const char *fmt, ...); #define reiserfs_panic(s, id, fmt, args...) \ - __reiserfs_panic(s, id, __func__, fmt, ##args) + do { __reiserfs_panic(s, id, __func__, fmt, ##args); BUG(); } while (0) void __reiserfs_error(struct super_block *s, const char *id, const char *function, const char *fmt, ...); #define reiserfs_error(s, id, fmt, args...) \
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