56 lines
1.7 KiB
Diff
56 lines
1.7 KiB
Diff
From 1836be5d99c9362f1e2b39206c95270f19cb7faa Mon Sep 17 00:00:00 2001
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From: Eric Sandeen <sandeen@redhat.com>
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Date: Wed, 5 Jun 2024 23:07:27 -0500
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Subject: [PATCH] fix hang when BLKTRACESETUP fails and "-o -" is used
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# blktrace -o - /dev/sda /dev/sdb /dev/sdc
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has to be SIGKILLed if BLKTRACESETUP fails for any or all of the devices
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listed. (I simulated this by just catching one of the devices in
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setup_buts(), skipping the ioctl, and doing ret++).
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This seems to be because with "-o -" on the command line, use_tracer_devpaths()
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sees piped_output set, so we call process_trace_bufs which ends up waiting on
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(!done) and "done" is never set. i.e.
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atexit(exit_tracing)
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wait_tracers
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if (use_tracer_devpaths()) // true because "-o -"
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process_trace_bufs
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while (wait_empty_entries())
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wait_empty_entries
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while (!done ... )
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<loop forever>
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I think this can be avoided by just setting "done = 1" before returning
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when setup_buts() fails in run_tracers().
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Signed-off-by: Eric Sandeen <sandeen@redhat.com>
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Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
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Link: https://lore.kernel.org/r/f3204c9d-1384-40b5-a5fb-3bb967ca2bec@redhat.com
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Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Signed-off-by: Pavel Reichl <preichl@redhat.com>
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---
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blktrace.c | 4 +++-
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1 file changed, 3 insertions(+), 1 deletion(-)
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diff --git a/blktrace.c b/blktrace.c
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index 3444fbb..038b2cb 100644
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--- a/blktrace.c
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+++ b/blktrace.c
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@@ -2684,8 +2684,10 @@ static int run_tracers(void)
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if (net_mode == Net_client)
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printf("blktrace: connecting to %s\n", hostname);
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- if (setup_buts())
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+ if (setup_buts()) {
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+ done = 1;
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return 1;
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+ }
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if (use_tracer_devpaths()) {
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if (setup_tracer_devpaths())
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--
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2.46.0
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