kernel/linux.git, branch v5.10.264

Linux 5.10.264

2026-08-07T06:06:53+00:00

Signed-off-by: Greg Kroah-Hartman

x86/bugs: Make Safe-RET robust against interrupt injection

2026-08-07T06:06:53+00:00

An attacker injecting interrupts while the Safe-RET mitigation executes on machines affected by SRSO can neutralize the safe return sequence, potentially leading to data leakage through speculative execution. Fixup register state as if the Safe-RET sequence executed successfully by "emulating" it, in a manner of speaking, and avoid executing a RET instruction after returning from the interrupt. Co-developed-by: David Kaplan Signed-off-by: David Kaplan Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Wenkuan Wang Signed-off-by: Greg Kroah-Hartman

Revert "x86/bugs: Make Safe-RET robust against interrupt injection"

2026-08-07T06:06:53+00:00

This reverts commit 9de1a49e8f1fbf7c372902573a27a97d4ab4d0af which is commit 7e7f81cf6f5ca3311e526308f55d7c54d3ba71f9 upstream. It was incorrect, a more correct fix will be applied next. Signed-off-by: Greg Kroah-Hartman

Linux 5.10.263

2026-08-06T17:21:31+00:00

Signed-off-by: Greg Kroah-Hartman

x86/bugs: Make Safe-RET robust against interrupt injection

2026-08-06T17:21:31+00:00

commit 7e7f81cf6f5ca3311e526308f55d7c54d3ba71f9 upstream. An attacker injecting interrupts while the Safe-RET mitigation executes on machines affected by SRSO can neutralize the safe return sequence, potentially leading to data leakage through speculative execution. Fixup register state as if the Safe-RET sequence executed successfully by "emulating" it, in a manner of speaking, and avoid executing a RET instruction after returning from the interrupt. Co-developed-by: David Kaplan Signed-off-by: David Kaplan Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Greg Kroah-Hartman

Linux 5.10.262

2026-07-30T10:56:00+00:00

Signed-off-by: Greg Kroah-Hartman

posix-cpu-timers: Prevent UAF caused by non-leader exec() race

2026-07-30T10:56:00+00:00

commit 920f893f735e92ba3a1cd9256899a186b161928d upstream. Wongi and Jungwoo decoded and reported a non-leader exec() related race which can result in an UAF: sys_timer_delete() exec() posix_cpu_timer_del() // Observes old leader p = pid_task(pid, pid_type); de_thread() switch_leader(); release_task(old_leader) __exit_signal(old_leader) sighand = lock(old_leader, sighand); posix_cpu_timers*_exit(); sighand = lock_task_sighand(p) unhash_task(old_leader); sh = lock(p, sighand) old_leader->sighand = NULL; unlock(sighand); (p->sighand == NULL) unlock(sh) return NULL; // Returns without action if(!sighand) return 0; free_posix_timer(); This is "harmless" unless the deleted timer was armed and enqueued in p->signal because on exec() a TGID targeted timer is inherited. As sys_timer_delete() freed the underlying posix timer object run_posix_cpu_timers() or any timerqueue related add/delete operations on other timers will access the freed object's timerqueue node, which results in an UAF. There is a similar problem vs. posix_cpu_timer_set(). For regular posix timers it just transiently returns -ESRCH to user space, but for the use case in do_cpu_nanosleep() it's the same UAF just that the k_itimer is allocated on the stack. Also posix_cpu_timer_rearm() fails to rearm the timer, which means it stops to expire. While debating solutions Frederic pointed out another problem: posix_cpu_timer_del(tmr) __exit_signal(p) posix_cpu_timers*_exit(p); unhash_task(p); p->sighand = NULL; sh = lock_task_sighand(p) sighand = p->sighand; if (!sighand) return NULL; lock(sighand); if (!sh) WARN_ON_ONCE(timer_queued(tmr)); On weakly ordered architectures it is not guaranteed that posix_cpu_timer_del() will observe the stores in posix_cpu_timers*_exit() when p->sighand is observed as NULL, which means the WARN() can be a false positive. Solve these issues by: 1) Changing the store in __exit_signal() to smp_store_release(). 2) Adding a smp_acquire__after_ctrl_dep() into the !sighand path of lock_task_sighand(). 3) Creating a helper function for looking up the task and locking sighand which does not return when sighand == NULL. Instead it retries the task lookup and only if that fails it gives up. 4) Using that helper in the three affected functions. #1/#2 ensures that the reader side which observes sighand == NULL also observes all preceeding stores, i.e. the stores in posix_cpu_timers*_exit() and the ones in unhash_task(). #3 ensures that the above described non-leader exec() situation is handled gracefully. When the task lookup returns the old leader, but sighand == NULL then it retries. In the non-leader exec() case the subsequent task lookup will observe the new leader due to #1/#2. In normal exit() scenarios the subsequent lookup fails. When the task lookup fails, the function also checks whether the timer is still enqueued and issues a warning if that's the case. Unfortunately there is nothing which can be done about it, but as the task is already not longer visible the timer should not be accessed anymore. This check also requires memory ordering, which is not provided when the first lookup fails. To achieve that the check is preceeded by a smp_rmb() which pairs with the smp_wmb() in write_seqlock() in __exit_signal(). That ensures that the stores in posix_cpu_timers*_exit() are visible. The history of the non-leader exec() issue goes back to the early days of posix CPU timers, which stored a pointer to the group leader task in the timer. That obviously fails when a non-leader exec() switches the leader. commit e0a70217107e ("posix-cpu-timers: workaround to suppress the problems with mt exec") added a temporary workaround for that in 2010 which survived about 10 years. The fix for the workaround changed the task pointer to a pid pointer, but failed to see the subtle race described above. So the Fixes tag picks that commit, which seems to be halfways accurate. Thanks to Frederic Weissbecker, Oleg Nesterov and Peter Zijlstra for review, feedback and suggestions and to Wongi and Jungwoo for the excellent bug report and analysis! Fixes: 55e8c8eb2c7b ("posix-cpu-timers: Store a reference to a pid not a task") Reported-by: Wongi Lee Reported-by: Jungwoo Lee Signed-off-by: Thomas Gleixner Reviewed-by: Oleg Nesterov Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin

Linux 5.10.261

2026-07-24T13:49:24+00:00

Link: https://lore.kernel.org/r/20260721152355.667394603@linuxfoundation.org Tested-by: Woody Suwalski Tested-by: Brett A C Sheffield Tested-by: Dominique Martinet Link: https://lore.kernel.org/r/20260722142749.280611149@linuxfoundation.org Tested-by: Brett A C Sheffield Tested-by: Florian Fainelli Tested-by: Pavel Machek (CIP) Tested-by: Mark Brown Tested-by: Barry K. Nathan Signed-off-by: Greg Kroah-Hartman

tools/resolve_btfids: Emit warnings and patch zero id for missing symbols

2026-07-24T13:49:24+00:00

commit 5aad03685185b5133a28e1ee1d4e98d3fd3642a3 upstream. Kernel functions referenced by .BTF_ids may be changed from global to static and get inlined or get renamed/removed, and thus disappears from BTF. This causes kernel build failure when resolve_btfids do id patch for symbols in .BTF_ids in vmlinux. Update resolve_btfids to emit warning messages and patch zero id for missing symbols instead of aborting kernel build process. Suggested-by: Andrii Nakryiko Signed-off-by: Hengqi Chen Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20210727132532.2473636-2-hengqi.chen@gmail.com Cc: "Barry K. Nathan" Signed-off-by: Greg Kroah-Hartman

tools/resolve_btfids: Fix some error messages

2026-07-24T13:49:24+00:00

commit 22e8ebe35a2e30ee19e02c41cacc99c2f896bc4b upstream. Add missing newlines and fix polarity of strerror argument. Signed-off-by: Brendan Jackman Signed-off-by: Alexei Starovoitov Acked-by: Jiri Olsa Link: https://lore.kernel.org/bpf/20201203102234.648540-1-jackmanb@google.com Cc: "Barry K. Nathan" Signed-off-by: Greg Kroah-Hartman