From: Ilya Leoshkevich <iii@linux.ibm.com>
To: Steven Rostedt <rostedt@goodmis.org>,
Alexander Potapenko <glider@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Lameter <cl@linux.com>,
David Rientjes <rientjes@google.com>,
Heiko Carstens <hca@linux.ibm.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Marco Elver <elver@google.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Pekka Enberg <penberg@kernel.org>,
Vasily Gorbik <gor@linux.ibm.com>,
Vlastimil Babka <vbabka@suse.cz>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Dmitry Vyukov <dvyukov@google.com>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>,
kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, linux-s390@vger.kernel.org,
linux-trace-kernel@vger.kernel.org,
Mark Rutland <mark.rutland@arm.com>,
Roman Gushchin <roman.gushchin@linux.dev>,
Sven Schnelle <svens@linux.ibm.com>
Subject: Re: [PATCH v2 01/33] ftrace: Unpoison ftrace_regs in ftrace_ops_list_func()
Date: Tue, 12 Dec 2023 03:05:25 +0100 [thread overview]
Message-ID: <3897a38ef97742f7f51fb4c84c5ddeb4e36dae79.camel@linux.ibm.com> (raw)
In-Reply-To: <20231208093133.62aae274@gandalf.local.home>
On Fri, 2023-12-08 at 09:31 -0500, Steven Rostedt wrote:
> On Fri, 8 Dec 2023 15:16:10 +0100
> Alexander Potapenko <glider@google.com> wrote:
>
> > On Tue, Nov 21, 2023 at 11:02 PM Ilya Leoshkevich
> > <iii@linux.ibm.com> wrote:
> > >
> > > Architectures use assembly code to initialize ftrace_regs and
> > > call
> > > ftrace_ops_list_func(). Therefore, from the KMSAN's point of
> > > view,
> > > ftrace_regs is poisoned on ftrace_ops_list_func entry(). This
> > > causes
> > > KMSAN warnings when running the ftrace testsuite.
> >
> > I couldn't reproduce these warnings on x86, hope you really need
> > this
> > change on s390 :)
I just double-checked, and it's still needed. Without it, I get:
[ 4.140184] =====================================================
[ 4.140416] BUG: KMSAN: uninit-value in
arch_ftrace_ops_list_func+0x8e6/0x14b0
[ 4.140484] arch_ftrace_ops_list_func+0x8e6/0x14b0
[ 4.140546] ftrace_graph_caller+0x0/0x34
[ 4.140614] read_tod_clock+0x6/0x1e0
[ 4.140671] ktime_get+0x3a4/0x670
[ 4.140727] clockevents_program_event+0x1c8/0xb10
[ 4.140785] tick_program_event+0x11e/0x230
[ 4.140842] hrtimer_interrupt+0x118a/0x1d10
[ 4.140898] do_IRQ+0x108/0x150
[ 4.140959] do_irq_async+0xfc/0x270
[ 4.141021] do_ext_irq+0x98/0x120
[ 4.141080] ext_int_handler+0xc4/0xf0
[ 4.141141] _raw_spin_unlock_irqrestore+0xfa/0x190
[ 4.141207] _raw_spin_unlock_irqrestore+0xf6/0x190
[ 4.141271] s390_kernel_write+0x218/0x250
[ 4.141328] ftrace_make_call+0x362/0x4a0
[ 4.141386] __ftrace_replace_code+0xb44/0xbd0
[ 4.141442] ftrace_replace_code+0x1d8/0x440
[ 4.141497] ftrace_modify_all_code+0xfe/0x510
[ 4.141555] ftrace_startup+0x4f0/0xcf0
[ 4.141609] register_ftrace_function+0x1316/0x1440
[ 4.141670] function_trace_init+0x2c0/0x3d0
[ 4.141732] tracer_init+0x282/0x370
[ 4.141789] trace_selftest_startup_function+0x104/0x19d0
[ 4.141857] run_tracer_selftest+0x7c8/0xab0
[ 4.141918] init_trace_selftests+0x200/0x820
[ 4.141977] do_one_initcall+0x35e/0x1090
[ 4.142032] do_initcall_level+0x276/0x660
[ 4.142095] do_initcalls+0x16a/0x2d0
[ 4.142153] kernel_init_freeable+0x632/0x960
[ 4.142216] kernel_init+0x36/0x1810
[ 4.142277] __ret_from_fork+0xc0/0x180
[ 4.142333] ret_from_fork+0xa/0x30
[ 4.142431] Local variable agg.tmp.i.i created at:
02:06:55 [30/1836]
[ 4.142476] timekeeping_advance+0x79a/0x2870
[ 4.142394]
[ 4.142431] Local variable agg.tmp.i.i created at:
[ 4.142476] timekeeping_advance+0x79a/0x2870
[ 4.142534]
[ 4.142573] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W
6.7.0-rc4-g7657d31dc545 #4
[ 4.142638] Hardware name: IBM 3931 A01 704 (KVM/Linux)
[ 4.142686] =====================================================
[ 4.142734] Kernel panic - not syncing: kmsan.panic set ...
[ 4.142734] =====================================================
> On x86, ftrace_regs sits on the stack. And IIUC, s390 doesn't have
> the same
> concept of a "stack" as other architectures. Perhaps that's the
> reason s390
> needs this?
It's not that different on s390x. There is indeed no architecture-
mandated stack pointer and no push/pop, but other than that it's fairly
normal. Linux uses %r15 as a stack pointer.
On s390x ftrace_regs is allocated on stack by mcount.S. From what I can
see, Intel's ftrace_64.S does the same thing, so I don't immediately
see why uninit-value is not detected on Intel, even though I think it
should.
> -- Steve
next prev parent reply other threads:[~2023-12-12 2:05 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-21 22:00 [PATCH v2 00/33] kmsan: Enable on s390 Ilya Leoshkevich
2023-11-21 22:00 ` [PATCH v2 01/33] ftrace: Unpoison ftrace_regs in ftrace_ops_list_func() Ilya Leoshkevich
2023-11-22 23:32 ` Steven Rostedt
2023-12-08 14:16 ` Alexander Potapenko
2023-12-08 14:31 ` Steven Rostedt
2023-12-12 2:05 ` Ilya Leoshkevich [this message]
2023-11-21 22:00 ` [PATCH v2 02/33] kmsan: Make the tests compatible with kmsan.panic=1 Ilya Leoshkevich
2023-11-21 22:00 ` [PATCH v2 03/33] kmsan: Disable KMSAN when DEFERRED_STRUCT_PAGE_INIT is enabled Ilya Leoshkevich
2023-11-21 22:00 ` [PATCH v2 04/33] kmsan: Increase the maximum store size to 4096 Ilya Leoshkevich
2023-12-08 16:31 ` Alexander Potapenko
2023-11-21 22:00 ` [PATCH v2 05/33] kmsan: Fix is_bad_asm_addr() on arches with overlapping address spaces Ilya Leoshkevich
2023-12-11 9:52 ` Alexander Potapenko
2023-11-21 22:01 ` [PATCH v2 06/33] kmsan: Fix kmsan_copy_to_user() " Ilya Leoshkevich
2023-11-21 22:01 ` [PATCH v2 07/33] kmsan: Remove a useless assignment from kmsan_vmap_pages_range_noflush() Ilya Leoshkevich
2023-11-21 22:01 ` [PATCH v2 08/33] kmsan: Remove an x86-specific #include from kmsan.h Ilya Leoshkevich
2023-11-21 22:01 ` [PATCH v2 09/33] kmsan: Introduce kmsan_memmove_metadata() Ilya Leoshkevich
2023-12-08 16:51 ` Alexander Potapenko
2023-11-21 22:01 ` [PATCH v2 10/33] kmsan: Expose kmsan_get_metadata() Ilya Leoshkevich
2023-12-11 10:07 ` Alexander Potapenko
2023-11-21 22:01 ` [PATCH v2 11/33] kmsan: Export panic_on_kmsan Ilya Leoshkevich
2023-11-21 22:01 ` [PATCH v2 12/33] kmsan: Allow disabling KMSAN checks for the current task Ilya Leoshkevich
2023-12-11 11:50 ` Alexander Potapenko
2023-12-13 15:01 ` Ilya Leoshkevich
2023-11-21 22:01 ` [PATCH v2 13/33] kmsan: Introduce memset_no_sanitize_memory() Ilya Leoshkevich
2023-12-08 13:48 ` Alexander Potapenko
2023-12-08 14:07 ` Ilya Leoshkevich
2023-12-08 15:25 ` Alexander Potapenko
2023-12-13 1:31 ` Ilya Leoshkevich
2023-12-13 11:32 ` Ilya Leoshkevich
2023-11-21 22:01 ` [PATCH v2 14/33] kmsan: Support SLAB_POISON Ilya Leoshkevich
2023-12-08 13:51 ` Alexander Potapenko
2023-11-21 22:01 ` [PATCH v2 15/33] kmsan: Use ALIGN_DOWN() in kmsan_get_metadata() Ilya Leoshkevich
2023-11-21 22:01 ` [PATCH v2 16/33] mm: slub: Let KMSAN access metadata Ilya Leoshkevich
2023-11-30 15:26 ` Vlastimil Babka
2023-11-21 22:01 ` [PATCH v2 17/33] mm: kfence: Disable KMSAN when checking the canary Ilya Leoshkevich
2023-12-08 12:53 ` Alexander Potapenko
2023-12-08 13:55 ` Alexander Potapenko
2023-11-21 22:01 ` [PATCH v2 18/33] lib/string: Add KMSAN support to strlcpy() and strlcat() Ilya Leoshkevich
2023-12-08 16:50 ` Alexander Potapenko
2023-12-13 0:53 ` Ilya Leoshkevich
2023-11-21 22:01 ` [PATCH v2 19/33] lib/zlib: Unpoison DFLTCC output buffers Ilya Leoshkevich
2023-12-08 13:32 ` Alexander Potapenko
2023-12-08 14:14 ` Ilya Leoshkevich
2023-12-08 14:25 ` Alexander Potapenko
2023-11-21 22:01 ` [PATCH v2 20/33] kmsan: Accept ranges starting with 0 on s390 Ilya Leoshkevich
2023-11-21 22:01 ` [PATCH v2 21/33] s390: Turn off KMSAN for boot, vdso and purgatory Ilya Leoshkevich
2023-11-21 22:01 ` [PATCH v2 22/33] s390: Use a larger stack for KMSAN Ilya Leoshkevich
2023-11-21 22:01 ` [PATCH v2 23/33] s390/boot: Add the KMSAN runtime stub Ilya Leoshkevich
2023-12-08 16:56 ` Alexander Potapenko
2023-11-21 22:01 ` [PATCH v2 24/33] s390/checksum: Add a KMSAN check Ilya Leoshkevich
2023-12-08 13:38 ` Alexander Potapenko
2023-11-21 22:01 ` [PATCH v2 25/33] s390/cpacf: Unpoison the results of cpacf_trng() Ilya Leoshkevich
2023-12-11 10:36 ` Alexander Potapenko
2023-11-21 22:01 ` [PATCH v2 26/33] s390/ftrace: Unpoison ftrace_regs in kprobe_ftrace_handler() Ilya Leoshkevich
2023-12-08 14:18 ` Alexander Potapenko
2023-11-21 22:01 ` [PATCH v2 27/33] s390/mm: Define KMSAN metadata for vmalloc and modules Ilya Leoshkevich
2023-12-11 10:13 ` Alexander Potapenko
2023-11-21 22:01 ` [PATCH v2 28/33] s390/string: Add KMSAN support Ilya Leoshkevich
2023-12-11 10:49 ` Alexander Potapenko
2023-11-21 22:01 ` [PATCH v2 29/33] s390/traps: Unpoison the kernel_stack_overflow()'s pt_regs Ilya Leoshkevich
2023-11-21 22:01 ` [PATCH v2 30/33] s390/uaccess: Add KMSAN support to put_user() and get_user() Ilya Leoshkevich
2023-12-11 10:46 ` Alexander Potapenko
2023-11-21 22:01 ` [PATCH v2 31/33] s390/unwind: Disable KMSAN checks Ilya Leoshkevich
2023-11-21 22:01 ` [PATCH v2 32/33] s390: Implement the architecture-specific kmsan functions Ilya Leoshkevich
2023-12-11 10:26 ` Alexander Potapenko
2023-12-11 10:39 ` Ilya Leoshkevich
2023-12-11 10:45 ` Alexander Potapenko
2023-11-21 22:01 ` [PATCH v2 33/33] kmsan: Enable on s390 Ilya Leoshkevich
2023-11-29 9:19 ` Alexander Potapenko
2023-11-29 9:58 ` Ilya Leoshkevich
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