diff options
| author | Benjamin Berg <benjamin@sipsolutions.net> | 2025-06-02 15:00:49 +0200 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2025-06-02 15:17:19 +0200 |
| commit | 8420e08fe3a594b6ffa07705ac270faa2ed452c5 (patch) | |
| tree | 22b578adabd9ef875fdaf560bd8d6a37eb8309b6 /arch/um/include/shared/skas/mm_id.h | |
| parent | b1e1bd2e69430445021394536740352be1b41cd0 (diff) | |
um: Track userspace children dying in SECCOMP mode
When in seccomp mode, we would hang forever on the futex if a child has
died unexpectedly. In contrast, ptrace mode will notice it and kill the
corresponding thread when it fails to run it.
Fix this issue using a new IRQ that is fired after a SIGCHLD and keeping
an (internal) list of all MMs. In the IRQ handler, find the affected MM
and set its PID to -1 as well as the futex variable to FUTEX_IN_KERN.
This, together with futex returning -EINTR after the signal is
sufficient to implement a race-free detection of a child dying.
Note that this also enables IRQ handling while starting a userspace
process. This should be safe and SECCOMP requires the IRQ in case the
process does not come up properly.
Signed-off-by: Benjamin Berg <benjamin@sipsolutions.net>
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20250602130052.545733-5-benjamin@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'arch/um/include/shared/skas/mm_id.h')
| -rw-r--r-- | arch/um/include/shared/skas/mm_id.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/um/include/shared/skas/mm_id.h b/arch/um/include/shared/skas/mm_id.h index 140388c282f6..0654c57bb28e 100644 --- a/arch/um/include/shared/skas/mm_id.h +++ b/arch/um/include/shared/skas/mm_id.h @@ -14,4 +14,6 @@ struct mm_id { void __switch_mm(struct mm_id *mm_idp); +void notify_mm_kill(int pid); + #endif |