Red Hat Bugzilla – Bug 618602
core_pattern handler truncates parameters
Last modified: 2011-07-29 09:23:35 EDT
Development version of abrt intended to fix bug 614486 sets /proc/sys/kernel/core_pattern to: echo "|/usr/libexec/abrt-hook-ccpp /var/spool/abrt %s %c %p %u %g %t 11 1234567890123456789012345678901234567890" >/proc/sys/kernel/core_pattern but on invocation, the parameters are: Jul 27 12:59:17 dhcp-25-227 abrt[25678]: argv[0]='/usr/libexec/abrt-hook-ccpp' Jul 27 12:59:17 dhcp-25-227 abrt[25678]: argv[1]='/var/spool/abrt' Jul 27 12:59:17 dhcp-25-227 abrt[25678]: argv[2]='6' Jul 27 12:59:17 dhcp-25-227 abrt[25678]: argv[3]='18446744073709551615' Jul 27 12:59:17 dhcp-25-227 abrt[25678]: argv[4]='25677' Jul 27 12:59:17 dhcp-25-227 abrt[25678]: argv[5]='0' Jul 27 12:59:17 dhcp-25-227 abrt[25678]: argv[6]='0' Jul 27 12:59:17 dhcp-25-227 abrt[25678]: argv[7]='1280228357' Jul 27 12:59:17 dhcp-25-227 abrt[25678]: argv[8]='11' Jul 27 12:59:17 dhcp-25-227 abrt[25678]: argv[9]='123456789012345678901234567890' Note that argv[9] is truncated. Please raise the limit of core_pattern handler parameter length in the relevant part of kernel code, it is too small.
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Patch(es) available on kernel-2.6.32-83.el6
Testing the fix for bug 614486 with kernel-2.6.32-83.el6. I set /proc/sys/kernel/core_pattern to: echo really_long_long_long_long_long_long_long_long_corename_s%s_c%c_p%p_u%u_g%g_t%t_h%h_e%e >/proc/sys/kernel/core_pattern When abrt starts, it sets core_pattern to: |/usr/libexec/abrt-hook-ccpp /var/spool/abrt %s %c %p %u %g %t %h %e 7265616c6c795f6c6f6e675f6c6f6e675f6c6f6e675f6c6f6e675f6c6f6e675f6c6f6e675f6c6f6e675f6c6f6e675f636f72656e616d655f7325735f6325635f7025705f7525755f6725675f7425745f6825685f652565 The long hex string is a hex-encoded "really_long_long_long_long_long_long_long_long_corename_s%s_c%c_p%p_u%u_g%g_t%t_h%h_e%e" But only "|/usr/libexec/abrt-hook-ccpp /var/spool/abrt %s %c %p %u %g %t %h %e 7265616c6c795f6c6f6e675f6c6f6e675f6c6f6e675f6c6f6e675f6c6f" makes it (127 chars). As a result, abrt-hook-ccpp saves coredump under truncated name "really_long_long_long_long_lo" I'd say that for most real-world cases it will work, but raising the 128 char limit would be appreciated.
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2011-0542.html
We have a test case for this issue but I not sure it's correct. What are the expectations on core_pattern here to be? Here comes the important lines from the test: rlPhaseStartSetup rlServiceStop abrt-ccpp core_pattern_bkp="$(cat /proc/sys/kernel/core_pattern)" rlLog "Former core_pattern was: $core_pattern_bkp" rlPhaseEnd rlPhaseStartTest rlRun "echo really_long_long_long_long_long_long_long_long_corename_s%s_c%c_p%p_u%u_g%g_t%t_h%h_e%e > /proc/sys/kernel/core_pattern" 0 "Set core_pattern to long garbage" rlServiceStart abrtd chars_in_core_pattern="$[$(cat /proc/sys/kernel/core_pattern | wc -c) - 1]" rlAssertGreaterOrEqual "core_pattern length should be >= 127" $chars_in_core_pattern 127 rlPhaseEnd rlPhaseStartCleanup rlServiceRestore abrt-ccpp rlLog "core_pattern is $(cat /proc/sys/kernel/core_pattern)" rlPhaseEnd What I know is wrong is that core_patter length was not extended beyond 128 chars. How should be the test written?