From: Jiri Olsa <jolsa@redhat.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Al Viro <viro@ZenIV.linux.org.uk>,
Tom Zanussi <tom.zanussi@linux.intel.com>,
Namhyung Kim <namhyung@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Jiri Olsa <jolsa@kernel.org>
Subject: Re: [PATCH 3/3] tracing: Rewrite filter logic to be simpler and faster
Date: Mon, 12 Mar 2018 16:10:17 +0100 [thread overview]
Message-ID: <20180312151017.GE23111@krava> (raw)
In-Reply-To: <20180310023907.798690563@goodmis.org>
On Fri, Mar 09, 2018 at 09:34:45PM -0500, Steven Rostedt wrote:
> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
>
> Al Viro reviewed the filter logic of ftrace trace events and found it to be
> very troubling. It creates a binary tree based on the logic operators and
> walks it during tracing. He sent myself and Tom Zanussi a long explanation
> (and formal proof) of how to do the string parsing better and end up with a
> program array that can be simply iterated to come up with the correct
> results.
>
> I took his ideas and his pseudo code and rewrote the filter logic based on
> them. In doing so, I was able to remove a lot of code, and have a much more
> condensed filter logic in the process. I wrote a very long comment
> describing the methadology that Al proposed in my own words. For more info
> on how this works, read the comment above predicate_parse().
>
> Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
got it crashed when clearing the filter via 'echo > filter'
jirka
---
ibm-x3650m4-01 login: [ 803.551062] BUG: unable to handle kernel paging request at ffff972acc154c34
[ 803.558846] IP: process_preds+0x5e9/0x680
[ 803.563318] PGD 251bbf067 P4D 251bbf067 PUD 0
[ 803.568280] Oops: 0000 [#1] SMP PTI
[ 803.572172] Modules linked in: intel_rapl sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm igb irqbypass crct10dif_pclmul ptp crc32_pclmul ipmi_ssmi_msghandler intel_rapl_perf wmi i2c_i801 mii lpc_ich xfs libcrc32c mgag200 i2c_algo_bit drm_kms_helper ttm crc32c_intel drm megaraid_sas
[ 803.618767] CPU: 13 PID: 1297 Comm: bash Not tainted 4.16.0-rc4+ #96
[ 803.625857] Hardware name: IBM System x3650 M4 : -[7915E2G]-/00Y7683, BIOS -[VVE124AUS-1.30]- 11/21/2012
[ 803.636441] RIP: 0010:process_preds+0x5e9/0x680
[ 803.641496] RSP: 0018:ffffa8aac2b9fd30 EFLAGS: 00010286
[ 803.647327] RAX: ffff972375def4e0 RBX: ffff972575b84e08 RCX: 00000000fffffffe
[ 803.655289] RDX: ffff972acc154c30 RSI: ffff972375def500 RDI: 0000000000023ee0
[ 803.663251] RBP: ffff972575b84198 R08: ffff972377be3ee0 R09: ffff972575b84210
[ 803.671213] R10: 0000000000000000 R11: 0000000040000000 R12: ffff972575b84ff0
[ 803.679176] R13: 0000000000000001 R14: 00000000fffffff4 R15: ffff972575b84ff0
[ 803.687139] FS: 00007f216a513700(0000) GS:ffff972377bc0000(0000) knlGS:0000000000000000
[ 803.696169] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 803.702581] CR2: ffff972acc154c34 CR3: 0000000274478001 CR4: 00000000000606e0
[ 803.710544] Call Trace:
[ 803.713278] create_filter+0x80/0xc0
[ 803.717268] apply_event_filter+0xb8/0x120
[ 803.721837] event_filter_write+0x5d/0xb0
[ 803.726312] __vfs_write+0x33/0x170
[ 803.730207] ? __inode_security_revalidate+0x4a/0x70
[ 803.735740] ? selinux_file_permission+0xce/0x120
[ 803.740989] ? _cond_resched+0x16/0x40
[ 803.745173] vfs_write+0xb0/0x190
[ 803.748870] SyS_write+0x52/0xc0
[ 803.752473] do_syscall_64+0x6e/0x180
[ 803.756560] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 803.762196] RIP: 0033:0x7f2169c00b50
[ 803.766182] RSP: 002b:00007ffc35e05db8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 803.774630] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f2169c00b50
[ 803.782592] RDX: 0000000000000001 RSI: 0000560031449e00 RDI: 0000000000000001
[ 803.790555] RBP: 0000560031449e00 R08: 00007f2169ecb740 R09: 00007f216a513700
[ 803.798517] R10: 0000560031453a00 R11: 0000000000000246 R12: 0000000000000001
[ 803.806479] R13: 0000000000000001 R14: 00007f2169eca5e0 R15: 00007f2169ec63c0
[ 803.814443] Code: 02 00 00 00 00 44 89 10 c7 40 04 00 00 00 00 83 e9 01 83 f9 ff 74 22 48 63 c1 48 c1 e0 04 48 01 f0 48 63 10 48 c1 e2 04 48 01 f2 <8b> 5a 04 39 58 04
[ 803.835544] RIP: process_preds+0x5e9/0x680 RSP: ffffa8aac2b9fd30
[ 803.842247] CR2: ffff972acc154c34
[ 803.845945] ---[ end trace 81df1915c389f53d ]---
next prev parent reply other threads:[~2018-03-12 15:10 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-10 2:34 [PATCH 0/3] tracing: Rewrite the function filter code Steven Rostedt
2018-03-10 2:34 ` [PATCH 1/3] tracing: Combine enum and arrays into single macro in " Steven Rostedt
2018-03-12 10:31 ` Masami Hiramatsu
2018-03-10 2:34 ` [PATCH 2/3] tracing: Clean up and document pred_funcs_##type creation and use Steven Rostedt
2018-03-12 13:42 ` Masami Hiramatsu
2018-03-10 2:34 ` [PATCH 3/3] tracing: Rewrite filter logic to be simpler and faster Steven Rostedt
2018-03-10 3:10 ` Steven Rostedt
2018-03-10 3:15 ` Steven Rostedt
2018-03-10 3:22 ` Steven Rostedt
2018-03-10 3:18 ` Steven Rostedt
2018-03-12 12:42 ` Jiri Olsa
2018-03-12 18:38 ` Steven Rostedt
2018-03-12 15:10 ` Jiri Olsa [this message]
2018-03-12 18:40 ` Steven Rostedt
2018-03-12 18:54 ` Jiri Olsa
2018-03-12 19:10 ` Steven Rostedt
2018-03-12 23:52 ` Steven Rostedt
2018-03-13 10:14 ` Jiri Olsa
2018-03-13 14:12 ` Steven Rostedt
2018-03-13 14:27 ` Jiri Olsa
2018-03-11 19:54 ` [PATCH 0/3] tracing: Rewrite the function filter code Jiri Olsa
-- strict thread matches above, loose matches on Subject: below --
2018-03-09 20:05 [PATCH v3] kernel.h: Skip single-eval logic on literals in min()/max() Kees Cook
2018-03-09 21:10 ` Linus Torvalds
2018-03-09 21:47 ` Kees Cook
2018-03-11 22:46 ` Tobin C. Harding
2018-03-13 13:31 ` David Laight
2018-03-10 0:07 ` Andrew Morton
2018-03-10 0:28 ` Linus Torvalds
2018-03-10 0:32 ` Andrew Morton
2018-03-10 0:38 ` Linus Torvalds
2018-03-10 1:30 ` Kees Cook
2018-03-10 1:31 ` Kees Cook
2018-03-10 2:37 ` Linus Torvalds
2018-03-12 22:55 ` Andrew Morton
2018-03-12 23:57 ` Linus Torvalds
2018-03-13 4:28 ` Kees Cook
2018-03-13 21:02 ` Andrew Morton
2018-03-13 22:14 ` Kees Cook
2018-03-14 11:35 ` David Laight
2018-03-10 3:11 ` Randy Dunlap
2018-03-10 6:10 ` Miguel Ojeda
2018-03-10 7:03 ` Miguel Ojeda
2018-03-10 16:04 ` Linus Torvalds
2018-03-10 15:33 ` Kees Cook
2018-03-10 16:11 ` Linus Torvalds
2018-03-10 16:30 ` Linus Torvalds
2018-03-10 17:34 ` Miguel Ojeda
2018-03-10 17:51 ` Linus Torvalds
2018-03-10 19:08 ` Miguel Ojeda
2018-03-11 11:05 ` Ingo Molnar
2018-03-11 18:23 ` Linus Torvalds
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