)]}'
{
  "commit": "c21eaa72f02fc6e85621cbe09d303d8fb8bd39cd",
  "tree": "bb4818f1f6127cdb05e08fe1869ece2e14465fed",
  "parents": [
    "acb03d3881818581052924a9bbbe92b8741ed448"
  ],
  "author": {
    "name": "Thomas Gleixner",
    "email": "tglx@kernel.org",
    "time": "Wed Sep 16 20:48:30 2026 +0200"
  },
  "committer": {
    "name": "Thomas Gleixner",
    "email": "tglx@kernel.org",
    "time": "Sat Sep 19 22:56:22 2026 +0200"
  },
  "message": "posix-cpu-timers: Prevent freeing a timer which is queued on the expiry list\n\nKijo analyzed another race in the POSIX CPU timer code:\n\nCommit bf635681c906 converted cpu_timer::firing from a tristate value to a\nboolean. This lost the distinction between \"not owned by the firing list\"\nand \"still owned, but delivery was canceled\". The resulting race is:\n\n    expiry handler              timer_settime()        timer_delete()\n    --------------              ---------------        --------------\n    collect timer onto\n    private firing list\n    firing \u003d true\n                                observes firing \u003d true\n                                firing \u003d false\n                                return TIMER_RETRY\n                                wait for handler\n                                                       observes firing \u003d false\n                                                       finish deletion\n                                                       unhash and free timer\n    resume list traversal\n    read freed elist.next\n    -\u003e UAF\n\nThe firing bit is clearly the wrong indicator since that commit.\n\nCheck whether the timer is queued on the expiry list or not instead. If it\nis queued clear the firing bit to prevent signal delivery as before and\nreturn TIMER_RETRY so the caller unlocks the timer which allows the expiry\ncode to make progress and remove it from the list.\n\nFixes: bf635681c906 (\"posix-cpu-timers: Cleanup the firing logic\")\nReported-by: Kijo Park \u003cred993688@gmail.com\u003e\nDebugged-by: Kijo Park \u003cred993688@gmail.com\u003e\nSigned-off-by: Thomas Gleixner \u003ctglx@kernel.org\u003e\nTested-by: Kijo Park \u003cred993688@gmail.com\u003e\nReviewed-by: Frederic Weisbecker \u003cfrederic@kernel.org\u003e\nCc: stable@vger.kernel.org\n",
  "tree_diff": [
    {
      "type": "modify",
      "old_id": "d73d31c7994fe111585022230b2c2ffcb7c3270e",
      "old_mode": 33188,
      "old_path": "kernel/time/posix-cpu-timers.c",
      "new_id": "0bf4fcd969c87e742dec271662d732a7fa9a9bf7",
      "new_mode": 33188,
      "new_path": "kernel/time/posix-cpu-timers.c"
    }
  ]
}