On 01/26/2018 09:15 AM, Metztli Information Technology wrote:
Niltze, Ed-

Hello.


I had been using Linux kernel 4.14.14 built 'the Debian way' for a couple of 
days
--doing some light VirtualBox development and successful virtual machine 
test/creation.

Notwithstanding, today 01-25-2018 experienced black screen kernel bug trace 
during browser usage.
I wrote down line number of reiser4 file.

FYI: No dataloss but had to reboot Debian AMD64 system due to 'kernel bug' at 
reference file/line:

invalid opcode: 0000 [#2] SMP PTI

file []-4.14.14/linux/fs/reiser4/block_alloc.c
--------------------------------------------------
[...]
/* Static functions for <reiser4 super block>/<reiser4 context> block counters
    arithmetic. Mostly, they are isolated to not to code same assertions in
    several places. */
static void sub_from_ctx_grabbed(reiser4_context * ctx, __u64 count)
{
         BUG_ON(ctx->grabbed_blocks < count); # kernel bug line 152
         assert("zam-527", ctx->grabbed_blocks >= count);
         ctx->grabbed_blocks -= count;
}
[...]

This is an old bug: a leak of grabbed disk space (reservation).
If it is reproducible, then one needs to insert debugging messages
to find out where the grabbed space disappears. Otherwise, there
is no other means except code review.

-----------------------------------------------------

In addition to usual prior mentioned specific Linux 4.14.x series logged 
entries during kernel builds:

fs/reiser4/carry.o: warning: objtool: fatal_carry_error.isra.5() falls through 
to next function print_level()
fs/reiser4/txnmgr.o: warning: objtool: commit_txnh()+0x580: stack state 
mismatch: cfa1=7+120 cfa2=7+136
fs/reiser4/flush.o: warning: objtool: reverse_allocate_parent() falls through 
to next function squalloc_right_twig_cut.isra.27()
fs/reiser4/wander.o: warning: objtool: reiser4_write_logs()+0x5a2: stack state 
mismatch: cfa1=7+184 cfa2=7+200
fs/reiser4/vfs_ops.o: warning: objtool: .text: unexpected end of section

I am aware of those warnings: a friendship with objtool is required.
Not of high priority.

Thanks,
Edward.

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