Backport #7402: Avoid calling methods on user objects from segfault handler

• Status: Closed
• Assignee: usa (Usaku NAKAMURA)

When the segfault handler is listing loaded features, it iterates through $LOADED_FEATURES and calls StringValueCStr() on each item. This in turn calls #to_str on the object.

If a #to_str method is defined on a non-T_STRING, it is possible to have code run during the segfault handler. If an exception is raised or a tag is thrown, it is possible to escape the segfault handler and recover from a segmentation fault.

I've attached a patch that checks if an item in $LOADED_FEATURES is a T_STRING, and calls rb_any_to_s() if not. This will avoid calling any methods which could potentially call back into Ruby-land.

[mame (Yusuke Endoh)]

• Status changed from Open to Assigned
• Assignee set to ko1 (Koichi Sasada)
• Target version set to 2.0.0

[ko1 (Koichi Sasada)]

• Assignee changed from ko1 (Koichi Sasada) to nobu (Nobuyoshi Nakada)

nobu, could you check it?

[nobu (Nobuyoshi Nakada)]

• Status changed from Assigned to Closed
• % Done changed from 0 to 100

This issue was solved with changeset r38041.
Charlie, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

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vm_dump.c: no methods in segv handler

• vm_dump.c (rb_vm_bugreport): get rid of calling methods in sigsegv
  handler. based on a patch by charliesome (Charlie Somerville)
  [ruby-core:49573] [Bug #7402]

[nobu (Nobuyoshi Nakada)]

• Tracker changed from Bug to Backport
• Project changed from Ruby master to Backport193
• Status changed from Closed to Assigned
• Assignee changed from nobu (Nobuyoshi Nakada) to usa (Usaku NAKAMURA)
• Target version deleted (2.0.0)

[naruse (Yui NARUSE)]

• Status changed from Assigned to Closed

r38335 fixed testing issue: it generates garbage core file.