From: Sasha Levin Date: Sat, 9 Nov 2024 14:55:48 +0000 (-0500) Subject: Fixes for 6.6 X-Git-Tag: v5.15.172~54^2~3 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3af18da7f30c0e9f09bb77f49bfd40aa57fda410;p=thirdparty%2Fkernel%2Fstable-queue.git Fixes for 6.6 Signed-off-by: Sasha Levin --- diff --git a/queue-6.6/posix-cpu-timers-clear-tick_dep_bit_posix_timer-on-c.patch b/queue-6.6/posix-cpu-timers-clear-tick_dep_bit_posix_timer-on-c.patch new file mode 100644 index 00000000000..b302ad326d5 --- /dev/null +++ b/queue-6.6/posix-cpu-timers-clear-tick_dep_bit_posix_timer-on-c.patch @@ -0,0 +1,92 @@ +From 1c4299c7f6a1ce55bb492a4ca9d53b1e32d3d9ba Mon Sep 17 00:00:00 2001 +From: Sasha Levin +Date: Fri, 25 Oct 2024 18:35:35 -0700 +Subject: posix-cpu-timers: Clear TICK_DEP_BIT_POSIX_TIMER on clone + +From: Benjamin Segall + +[ Upstream commit b5413156bad91dc2995a5c4eab1b05e56914638a ] + +When cloning a new thread, its posix_cputimers are not inherited, and +are cleared by posix_cputimers_init(). However, this does not clear the +tick dependency it creates in tsk->tick_dep_mask, and the handler does +not reach the code to clear the dependency if there were no timers to +begin with. + +Thus if a thread has a cputimer running before clone/fork, all +descendants will prevent nohz_full unless they create a cputimer of +their own. + +Fix this by entirely clearing the tick_dep_mask in copy_process(). +(There is currently no inherited state that needs a tick dependency) + +Process-wide timers do not have this problem because fork does not copy +signal_struct as a baseline, it creates one from scratch. + +Fixes: b78783000d5c ("posix-cpu-timers: Migrate to use new tick dependency mask model") +Signed-off-by: Ben Segall +Signed-off-by: Thomas Gleixner +Reviewed-by: Frederic Weisbecker +Cc: stable@vger.kernel.org +Link: https://lore.kernel.org/all/xm26o737bq8o.fsf@google.com +Signed-off-by: Sasha Levin +--- + include/linux/tick.h | 8 ++++++++ + kernel/fork.c | 2 ++ + 2 files changed, 10 insertions(+) + +diff --git a/include/linux/tick.h b/include/linux/tick.h +index 9459fef5b8573..9701c571a5cfe 100644 +--- a/include/linux/tick.h ++++ b/include/linux/tick.h +@@ -252,12 +252,19 @@ static inline void tick_dep_set_task(struct task_struct *tsk, + if (tick_nohz_full_enabled()) + tick_nohz_dep_set_task(tsk, bit); + } ++ + static inline void tick_dep_clear_task(struct task_struct *tsk, + enum tick_dep_bits bit) + { + if (tick_nohz_full_enabled()) + tick_nohz_dep_clear_task(tsk, bit); + } ++ ++static inline void tick_dep_init_task(struct task_struct *tsk) ++{ ++ atomic_set(&tsk->tick_dep_mask, 0); ++} ++ + static inline void tick_dep_set_signal(struct task_struct *tsk, + enum tick_dep_bits bit) + { +@@ -291,6 +298,7 @@ static inline void tick_dep_set_task(struct task_struct *tsk, + enum tick_dep_bits bit) { } + static inline void tick_dep_clear_task(struct task_struct *tsk, + enum tick_dep_bits bit) { } ++static inline void tick_dep_init_task(struct task_struct *tsk) { } + static inline void tick_dep_set_signal(struct task_struct *tsk, + enum tick_dep_bits bit) { } + static inline void tick_dep_clear_signal(struct signal_struct *signal, +diff --git a/kernel/fork.c b/kernel/fork.c +index 9098284720e38..23efaa2c42e4f 100644 +--- a/kernel/fork.c ++++ b/kernel/fork.c +@@ -99,6 +99,7 @@ + #include + #include + #include ++#include + + #include + #include +@@ -2418,6 +2419,7 @@ __latent_entropy struct task_struct *copy_process( + acct_clear_integrals(p); + + posix_cputimers_init(&p->posix_cputimers); ++ tick_dep_init_task(p); + + p->io_context = NULL; + audit_set_context(p, NULL); +-- +2.43.0 + diff --git a/queue-6.6/series b/queue-6.6/series index ad6ca1fd9fb..1760dd20438 100644 --- a/queue-6.6/series +++ b/queue-6.6/series @@ -71,3 +71,4 @@ ksmbd-fix-slab-use-after-free-in-ksmbd_smb2_session_create.patch ksmbd-check-outstanding-simultaneous-smb-operations.patch ksmbd-fix-the-missing-xa_store-error-check.patch ksmbd-fix-slab-use-after-free-in-smb3_preauth_hash_rsp.patch +posix-cpu-timers-clear-tick_dep_bit_posix_timer-on-c.patch