[PATCH 3.4 132/146] tracing: Have filter check for balanced ops
From: Steven Rostedt 3.4.109-rc1 review patch. If anyone has any objections, please let me know. -- commit 2cf30dc180cea808077f003c5116388183e54f9e upstream. When the following filter is used it causes a warning to trigger: # cd /sys/kernel/debug/tracing # echo "((dev==1)blocks==2)" > events/ext4/ext4_truncate_exit/filter -bash: echo: write error: Invalid argument # cat events/ext4/ext4_truncate_exit/filter ((dev==1)blocks==2) ^ parse_error: No error [ cut here ] WARNING: CPU: 2 PID: 1223 at kernel/trace/trace_events_filter.c:1640 replace_preds+0x3c5/0x990() Modules linked in: bnep lockd grace bluetooth ... CPU: 3 PID: 1223 Comm: bash Tainted: GW 4.1.0-rc3-test+ #450 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012 0668 8800c106bc98 816ed4f9 88011ead0cf0 8800c106bcd8 8107fb07 8136b46c 8800c7d81d48 8800d4c2bc00 8800d4d4f920 ffea Call Trace: [] dump_stack+0x4c/0x6e [] warn_slowpath_common+0x97/0xe0 [] ? _kstrtoull+0x2c/0x80 [] warn_slowpath_null+0x1a/0x20 [] replace_preds+0x3c5/0x990 [] create_filter+0x82/0xb0 [] apply_event_filter+0xd4/0x180 [] event_filter_write+0x8f/0x120 [] __vfs_write+0x28/0xe0 [] ? __sb_start_write+0x53/0xf0 [] ? security_file_permission+0x30/0xc0 [] vfs_write+0xb8/0x1b0 [] SyS_write+0x4f/0xb0 [] system_call_fastpath+0x12/0x6a ---[ end trace e11028bd95818dcd ]--- Worse yet, reading the error message (the filter again) it says that there was no error, when there clearly was. The issue is that the code that checks the input does not check for balanced ops. That is, having an op between a closed parenthesis and the next token. This would only cause a warning, and fail out before doing any real harm, but it should still not caues a warning, and the error reported should work: # cd /sys/kernel/debug/tracing # echo "((dev==1)blocks==2)" > events/ext4/ext4_truncate_exit/filter -bash: echo: write error: Invalid argument # cat events/ext4/ext4_truncate_exit/filter ((dev==1)blocks==2) ^ parse_error: Meaningless filter expression And give no kernel warning. Link: http://lkml.kernel.org/r/20150615175025.7e809...@gandalf.local.home Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Reported-by: Vince Weaver Tested-by: Vince Weaver Signed-off-by: Steven Rostedt [lizf: Backported to 3.4: remove the check for OP_NOT, as it's not supported.] Signed-off-by: Zefan Li --- kernel/trace/trace_events_filter.c | 10 -- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 289197a..3b04aec 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1357,19 +1357,25 @@ static int check_preds(struct filter_parse_state *ps) { int n_normal_preds = 0, n_logical_preds = 0; struct postfix_elt *elt; + int cnt = 0; list_for_each_entry(elt, >postfix, list) { - if (elt->op == OP_NONE) + if (elt->op == OP_NONE) { + cnt++; continue; + } if (elt->op == OP_AND || elt->op == OP_OR) { n_logical_preds++; + cnt--; continue; } + cnt--; n_normal_preds++; + WARN_ON_ONCE(cnt < 0); } - if (!n_normal_preds || n_logical_preds >= n_normal_preds) { + if (cnt != 1 || !n_normal_preds || n_logical_preds >= n_normal_preds) { parse_error(ps, FILT_ERR_INVALID_FILTER, 0); return -EINVAL; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 3.4 132/146] tracing: Have filter check for balanced ops
From: Steven Rostedt3.4.109-rc1 review patch. If anyone has any objections, please let me know. -- commit 2cf30dc180cea808077f003c5116388183e54f9e upstream. When the following filter is used it causes a warning to trigger: # cd /sys/kernel/debug/tracing # echo "((dev==1)blocks==2)" > events/ext4/ext4_truncate_exit/filter -bash: echo: write error: Invalid argument # cat events/ext4/ext4_truncate_exit/filter ((dev==1)blocks==2) ^ parse_error: No error [ cut here ] WARNING: CPU: 2 PID: 1223 at kernel/trace/trace_events_filter.c:1640 replace_preds+0x3c5/0x990() Modules linked in: bnep lockd grace bluetooth ... CPU: 3 PID: 1223 Comm: bash Tainted: GW 4.1.0-rc3-test+ #450 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012 0668 8800c106bc98 816ed4f9 88011ead0cf0 8800c106bcd8 8107fb07 8136b46c 8800c7d81d48 8800d4c2bc00 8800d4d4f920 ffea Call Trace: [] dump_stack+0x4c/0x6e [] warn_slowpath_common+0x97/0xe0 [] ? _kstrtoull+0x2c/0x80 [] warn_slowpath_null+0x1a/0x20 [] replace_preds+0x3c5/0x990 [] create_filter+0x82/0xb0 [] apply_event_filter+0xd4/0x180 [] event_filter_write+0x8f/0x120 [] __vfs_write+0x28/0xe0 [] ? __sb_start_write+0x53/0xf0 [] ? security_file_permission+0x30/0xc0 [] vfs_write+0xb8/0x1b0 [] SyS_write+0x4f/0xb0 [] system_call_fastpath+0x12/0x6a ---[ end trace e11028bd95818dcd ]--- Worse yet, reading the error message (the filter again) it says that there was no error, when there clearly was. The issue is that the code that checks the input does not check for balanced ops. That is, having an op between a closed parenthesis and the next token. This would only cause a warning, and fail out before doing any real harm, but it should still not caues a warning, and the error reported should work: # cd /sys/kernel/debug/tracing # echo "((dev==1)blocks==2)" > events/ext4/ext4_truncate_exit/filter -bash: echo: write error: Invalid argument # cat events/ext4/ext4_truncate_exit/filter ((dev==1)blocks==2) ^ parse_error: Meaningless filter expression And give no kernel warning. Link: http://lkml.kernel.org/r/20150615175025.7e809...@gandalf.local.home Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Reported-by: Vince Weaver Tested-by: Vince Weaver Signed-off-by: Steven Rostedt [lizf: Backported to 3.4: remove the check for OP_NOT, as it's not supported.] Signed-off-by: Zefan Li --- kernel/trace/trace_events_filter.c | 10 -- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 289197a..3b04aec 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1357,19 +1357,25 @@ static int check_preds(struct filter_parse_state *ps) { int n_normal_preds = 0, n_logical_preds = 0; struct postfix_elt *elt; + int cnt = 0; list_for_each_entry(elt, >postfix, list) { - if (elt->op == OP_NONE) + if (elt->op == OP_NONE) { + cnt++; continue; + } if (elt->op == OP_AND || elt->op == OP_OR) { n_logical_preds++; + cnt--; continue; } + cnt--; n_normal_preds++; + WARN_ON_ONCE(cnt < 0); } - if (!n_normal_preds || n_logical_preds >= n_normal_preds) { + if (cnt != 1 || !n_normal_preds || n_logical_preds >= n_normal_preds) { parse_error(ps, FILT_ERR_INVALID_FILTER, 0); return -EINVAL; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/