[Qemu-devel] [Bug 1429313] [NEW] qemu-user doesn't block target signals on entry to signal hanlder.

[Timothy Baldwin]

Public bug reported:

Upon entry to a target signal handler the function
process_pending_signals in linux-user/signal.c block the appropriate
host signals, but signals already received and queued by Qemu are not
blocked. If multiple signals arrive in quick succession this results
incorrect recursion in the target signal handler.

The attached test case my be run as:

$ (sleep 2 ; echo) | qemu-i386 ./a.out
.................. Recursion in signal handler!
qemu: uncaught target signal 6 (Aborted) - core dumped

** Affects: qemu
     Importance: Undecided
         Status: New

** Attachment added: "Testcase"
   https://bugs.launchpad.net/bugs/1429313/+attachment/4336774/+files/sigtest.c

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https://bugs.launchpad.net/bugs/1429313

Title:
  qemu-user doesn't block target signals on entry to signal hanlder.

Status in QEMU:
  New

Bug description:
  Upon entry to a target signal handler the function
  process_pending_signals in linux-user/signal.c block the appropriate
  host signals, but signals already received and queued by Qemu are not
  blocked. If multiple signals arrive in quick succession this results
  incorrect recursion in the target signal handler.

  The attached test case my be run as:

  $ (sleep 2 ; echo) | qemu-i386 ./a.out
  .................. Recursion in signal handler!
  qemu: uncaught target signal 6 (Aborted) - core dumped

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