Re: «run_pending_traps: bad value in trap_list» when `jobs` is run a trap

[Chet Ramey]

On 7/1/24 4:45 PM, Gioele Barabucci wrote:

Hi,

the following script (reduced from <https://bugs.debian.org/417946>)

     #!/bin/bash
     childfinished () { echo "jobs: $(jobs)"; }
     trap childfinished SIGCHLD
     sleep 1 &
     wait

causes bash 5.2.21 to output

     ./par.sh: line 2: warning: run_pending_traps:
     bad value in trap_list[17]: 0x5625e6fa43d0

Does this warning hint at something like a dangling reference that should be fixed, or can it be safely ignored?

It's warning you that you're recursively calling the SIGCHLD trap handler.
It's clearer when the debugging messages are enabled:

$ ./bash x2

jobs: [1]+  Done                       sleep 1

x2: line 2: warning: run_pending_traps: bad value in trap_list[20]: 0x102dc8a0c

We use the `bad value' as a sentinel to make sure the user can reset the
SIGCHLD disposition in the trap handler without run_trap_internal restoring
it to the original value.

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    c...@case.edu    http://tiswww.cwru.edu/~chet/

x2: line 2: DEBUG warning: wait_for: recursively setting old_sigint_handler to wait_sigint_handler: running_trap = 21 x2: line 2: DEBUG warning: run_pending_traps: recursive invocation while running trap for signal 20

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