From: Vlastimil Babka <vbabka@suse.cz>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Christoph Hellwig <hch@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Christoph Lameter <cl@linux.com>,
glittao@gmail.com, Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Linux-MM <linux-mm@kvack.org>,
mm-commits@vger.kernel.org, Pekka Enberg <penberg@kernel.org>,
Randy Dunlap <rdunlap@infradead.org>,
David Rientjes <rientjes@google.com>,
linux-xfs <linux-xfs@vger.kernel.org>,
Geert Uytterhoeven <geert@linux-m68k.org>
Subject: Re: [patch 07/54] mm/slub: use stackdepot to save stack trace in objects
Date: Sat, 17 Jul 2021 00:37:57 +0200 [thread overview]
Message-ID: <3eb0e8e4-adae-883d-1be9-a086f01197ff@suse.cz> (raw)
In-Reply-To: <CAHk-=whnjz19Ln3=s4rDZn4+XER2pmA+pEVrjpwMYGba2rHAQA@mail.gmail.com>
On 7/16/21 10:12 PM, Linus Torvalds wrote:
> On Fri, Jul 16, 2021 at 12:39 AM Christoph Hellwig <hch@infradead.org> wrote:
>>
>> This somewhat unexpectedly causes a crash when running the xfs/433 test
>> in xfstests for me. Reverting the commit fixes the problem:
>
> I don't see why that would be the case, but I'm inclined to revert
> that commit for another reason: the code doesn't seem to match the
> description of the commit.
>
> It used to be that CONFIG_SLUB_DEBUG was a config option that was
> harmless and that defaulted to 'y' because there was little downside.
> In fact, it's not just "default y", it doesn't even *ask* the user
> unless CONFIG_EXPERT is on. Because it was fairly harmless. And then
> SLOB_DEBUG_ON was that "do you actually want this code _enabled_".
>
> But now it basically force-enables that STACKDEPOT support too, and
> then instead of having an _optional_ CONFIG_STACKTRACE, you basically
> have that as being forced on you whether you want active debugging or
> not.
>
> Maybe that
>
> select STACKDEPOT if STACKTRACE_SUPPORT
>
> should have been
>
> select STACKDEPOT if STACKTRACE
I recall we tried that and run into KConfig recursive dependency hell as
"config STACKDEPOT" does "select STACKTRACE", and after some attempts
ended up with the above.
> because i\t used to be that CONFIG_STACKTRACE was somewhat unusual,
> and only enabled for special debug cases (admittedly "CONFIG_TRACING"
> likely meant that it was fairly widely enabled).
>
> In contrast, STACKTRACE_SUPPORT is basically "this architecture supports it".
>
> So now it seems STACKDEPOT is enabled basically unconditionally.
It seemed rather harmless as it was just a bit of extra code. But it's
true Geert reports [1] unexpected memory usage which I would have only
expected if actual stacks started to be collected. So I guess we'll have
to look into that.
[1]
https://lore.kernel.org/lkml/CAMuHMdW=eoVzM1Re5FVoEN87nKfiLmM2+Ah7eNu2KXEhCvbZyA@mail.gmail.com/
> So I really don't see why it would cause that xfs issue, but I think
> there are multiple reasons to just go "Hmm" on that commit.
>
> Comments?
>
> Linus
>
next prev parent reply other threads:[~2021-07-16 22:38 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-08 0:59 incoming Andrew Morton
2021-07-08 1:07 ` [patch 01/54] lib/test: fix spelling mistakes Andrew Morton
2021-07-08 1:07 ` [patch 02/54] lib: " Andrew Morton
2021-07-08 1:07 ` [patch 03/54] lib: fix spelling mistakes in header files Andrew Morton
2021-07-08 1:07 ` [patch 04/54] hexagon: handle {,SOFT}IRQENTRY_TEXT in linker script Andrew Morton
2021-07-08 1:07 ` [patch 05/54] hexagon: use common DISCARDS macro Andrew Morton
2021-07-08 1:07 ` [patch 06/54] hexagon: select ARCH_WANT_LD_ORPHAN_WARN Andrew Morton
2021-07-08 1:07 ` [patch 07/54] mm/slub: use stackdepot to save stack trace in objects Andrew Morton
2021-07-16 7:39 ` Christoph Hellwig
2021-07-16 8:57 ` Vlastimil Babka
2021-07-16 9:12 ` Christoph Hellwig
2021-07-16 20:12 ` Linus Torvalds
2021-07-16 22:37 ` Vlastimil Babka [this message]
2021-07-17 17:34 ` Randy Dunlap
2021-07-18 7:29 ` Vlastimil Babka
2021-07-18 14:17 ` Randy Dunlap
2021-07-08 1:07 ` [patch 08/54] mmap: make mlock_future_check() global Andrew Morton
2021-07-08 1:07 ` [patch 09/54] riscv/Kconfig: make direct map manipulation options depend on MMU Andrew Morton
2021-07-08 1:07 ` [patch 10/54] set_memory: allow querying whether set_direct_map_*() is actually enabled Andrew Morton
2021-07-08 1:08 ` [patch 11/54] mm: introduce memfd_secret system call to create "secret" memory areas Andrew Morton
2021-07-08 3:13 ` Linus Torvalds
2021-07-08 5:21 ` Mike Rapoport
2021-07-08 18:38 ` Linus Torvalds
2021-07-08 20:13 ` Hagen Paul Pfeifer
2021-07-09 15:44 ` Mike Rapoport
2021-07-08 1:08 ` [patch 12/54] PM: hibernate: disable when there are active secretmem users Andrew Morton
2021-07-08 3:15 ` Linus Torvalds
2021-07-08 5:30 ` Mike Rapoport
2021-07-08 1:08 ` [patch 13/54] arch, mm: wire up memfd_secret system call where relevant Andrew Morton
2021-07-08 1:08 ` [patch 14/54] secretmem: test: add basic selftest for memfd_secret(2) Andrew Morton
2021-07-08 1:08 ` [patch 15/54] mm: fix spelling mistakes in header files Andrew Morton
2021-07-08 1:08 ` [patch 16/54] mm: add setup_initial_init_mm() helper Andrew Morton
2021-07-08 1:08 ` [patch 17/54] arc: convert to setup_initial_init_mm() Andrew Morton
2021-07-08 1:08 ` [patch 18/54] arm: " Andrew Morton
2021-07-08 1:08 ` [patch 19/54] arm64: " Andrew Morton
2021-07-08 1:08 ` [patch 20/54] csky: " Andrew Morton
2021-07-08 1:08 ` [patch 21/54] h8300: " Andrew Morton
2021-07-08 1:08 ` [patch 22/54] m68k: " Andrew Morton
2021-07-08 1:08 ` [patch 23/54] nds32: " Andrew Morton
2021-07-08 1:08 ` [patch 24/54] nios2: " Andrew Morton
2021-07-08 1:08 ` [patch 25/54] openrisc: " Andrew Morton
2021-07-08 1:08 ` [patch 26/54] powerpc: " Andrew Morton
2021-07-08 4:46 ` Christophe Leroy
2021-07-08 1:08 ` [patch 27/54] riscv: " Andrew Morton
2021-07-08 1:08 ` [patch 28/54] s390: " Andrew Morton
2021-07-08 1:09 ` [patch 29/54] sh: " Andrew Morton
2021-07-08 1:09 ` [patch 30/54] x86: " Andrew Morton
2021-07-08 1:09 ` [patch 31/54] buildid: only consider GNU notes for build ID parsing Andrew Morton
2021-07-08 1:09 ` [patch 32/54] buildid: add API to parse build ID out of buffer Andrew Morton
2021-07-08 1:09 ` [patch 33/54] buildid: stash away kernels build ID on init Andrew Morton
2021-07-08 1:09 ` [patch 34/54] dump_stack: add vmlinux build ID to stack traces Andrew Morton
2021-07-08 1:09 ` [patch 35/54] module: add printk formats to add module build ID to stacktraces Andrew Morton
2021-07-08 1:09 ` [patch 36/54] arm64: stacktrace: use %pSb for backtrace printing Andrew Morton
2021-07-08 1:09 ` [patch 37/54] x86/dumpstack: use %pSb/%pBb " Andrew Morton
2021-07-08 1:09 ` [patch 38/54] scripts/decode_stacktrace.sh: support debuginfod Andrew Morton
2021-07-08 1:09 ` [patch 39/54] scripts/decode_stacktrace.sh: silence stderr messages from addr2line/nm Andrew Morton
2021-07-08 1:09 ` [patch 40/54] scripts/decode_stacktrace.sh: indicate 'auto' can be used for base path Andrew Morton
2021-07-08 1:09 ` [patch 41/54] buildid: mark some arguments const Andrew Morton
2021-07-08 1:09 ` [patch 42/54] buildid: fix kernel-doc notation Andrew Morton
2021-07-08 1:09 ` [patch 43/54] kdump: use vmlinux_build_id to simplify Andrew Morton
2021-07-08 1:09 ` [patch 44/54] mm: rename pud_page_vaddr to pud_pgtable and make it return pmd_t * Andrew Morton
2021-07-08 1:09 ` [patch 45/54] mm: rename p4d_page_vaddr to p4d_pgtable and make it return pud_t * Andrew Morton
2021-07-08 1:09 ` [patch 46/54] selftest/mremap_test: update the test to handle pagesize other than 4K Andrew Morton
2021-07-08 1:10 ` [patch 47/54] selftest/mremap_test: avoid crash with static build Andrew Morton
2021-07-08 1:10 ` [patch 48/54] mm/mremap: convert huge PUD move to separate helper Andrew Morton
2021-07-08 1:10 ` [patch 49/54] mm/mremap: don't enable optimized PUD move if page table levels is 2 Andrew Morton
2021-07-08 1:10 ` [patch 50/54] mm/mremap: use pmd/pud_poplulate to update page table entries Andrew Morton
2021-07-08 1:10 ` [patch 51/54] mm/mremap: hold the rmap lock in write mode when moving " Andrew Morton
2021-07-08 1:10 ` [patch 52/54] mm/mremap: allow arch runtime override Andrew Morton
2021-07-08 1:10 ` [patch 53/54] powerpc/book3s64/mm: update flush_tlb_range to flush page walk cache Andrew Morton
2021-07-08 1:10 ` [patch 54/54] powerpc/mm: enable HAVE_MOVE_PMD support Andrew Morton
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