On Thu, Jul 11, 2019 at 11:29 PM Arnd Bergmann <[email protected]> wrote: > > On Thu, Jul 11, 2019 at 11:05 PM 'Jann Horn' via Clang Built Linux > <[email protected]> wrote: > > I was playing around with building the kernel with LLVM a few months > > ago and used this local patch, but didn't get around to submitting > > upstream because I couldn't reproduce the problem for some reason. I > > think the warnings you're getting sound like what I saw back then: > > https://gist.github.com/thejh/0434662728afb95d72455bf30ece5817 > > > > Quoting the commit message from that patch: > > > > ==== > > With clang from git master, code can be generated where a function contains > > two indirect jump instructions that use the same switch table. To deal with > > this case and similar ones properly, convert the switch table parsing to > > use two passes: > > ==== > > > > Does that sound like what you're seeing? > > Yes, that is exactly right, and your patch seems to address the problem > for the cases I tried so far (will know more after a night of randconfig > testing).
I no longer see any of the "can't find switch jump table" in last
nights randconfig
builds. I do see one other rare warning, see attached object file:
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
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
I suspect this comes from the calls to the __reiserfs_panic() noreturn function,
but have not actually looked at the object file.
Arnd
lbalance.o
Description: application/object
