From: Greg Kroah-Hartman Date: Mon, 6 Mar 2023 10:57:48 +0000 (+0100) Subject: 4.14-stable patches X-Git-Tag: v6.2.3~108 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7bc2d683fac8ef9d2797c343f562c8a44211792d;p=thirdparty%2Fkernel%2Fstable-queue.git 4.14-stable patches added patches: s390-kprobes-fix-current_kprobe-never-cleared-after-kprobes-reenter.patch s390-kprobes-fix-irq-mask-clobbering-on-kprobe-reenter-from-post_handler.patch --- diff --git a/queue-4.14/s390-kprobes-fix-current_kprobe-never-cleared-after-kprobes-reenter.patch b/queue-4.14/s390-kprobes-fix-current_kprobe-never-cleared-after-kprobes-reenter.patch new file mode 100644 index 00000000000..8c15b322603 --- /dev/null +++ b/queue-4.14/s390-kprobes-fix-current_kprobe-never-cleared-after-kprobes-reenter.patch @@ -0,0 +1,54 @@ +From cd57953936f2213dfaccce10d20f396956222c7d Mon Sep 17 00:00:00 2001 +From: Vasily Gorbik +Date: Wed, 1 Mar 2023 17:58:06 +0100 +Subject: s390/kprobes: fix current_kprobe never cleared after kprobes reenter + +From: Vasily Gorbik + +commit cd57953936f2213dfaccce10d20f396956222c7d upstream. + +Recent test_kprobe_missed kprobes kunit test uncovers the following +problem. Once kprobe is triggered from another kprobe (kprobe reenter), +all future kprobes on this cpu are considered as kprobe reenter, thus +pre_handler and post_handler are not being called and kprobes are counted +as "missed". + +Commit b9599798f953 ("[S390] kprobes: activation and deactivation") +introduced a simpler scheme for kprobes (de)activation and status +tracking by using push_kprobe/pop_kprobe, which supposed to work for +both initial kprobe entry as well as kprobe reentry and helps to avoid +handling those two cases differently. The problem is that a sequence of +calls in case of kprobes reenter: +push_kprobe() <- NULL (current_kprobe) +push_kprobe() <- kprobe1 (current_kprobe) +pop_kprobe() -> kprobe1 (current_kprobe) +pop_kprobe() -> kprobe1 (current_kprobe) +leaves "kprobe1" as "current_kprobe" on this cpu, instead of setting it +to NULL. In fact push_kprobe/pop_kprobe can only store a single state +(there is just one prev_kprobe in kprobe_ctlblk). Which is a hack but +sufficient, there is no need to have another prev_kprobe just to store +NULL. To make a simple and backportable fix simply reset "prev_kprobe" +when kprobe is poped from this "stack". No need to worry about +"kprobe_status" in this case, because its value is only checked when +current_kprobe != NULL. + +Cc: stable@vger.kernel.org +Fixes: b9599798f953 ("[S390] kprobes: activation and deactivation") +Reviewed-by: Heiko Carstens +Signed-off-by: Vasily Gorbik +Signed-off-by: Heiko Carstens +Signed-off-by: Greg Kroah-Hartman +--- + arch/s390/kernel/kprobes.c | 1 + + 1 file changed, 1 insertion(+) + +--- a/arch/s390/kernel/kprobes.c ++++ b/arch/s390/kernel/kprobes.c +@@ -272,6 +272,7 @@ static void pop_kprobe(struct kprobe_ctl + { + __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp); + kcb->kprobe_status = kcb->prev_kprobe.status; ++ kcb->prev_kprobe.kp = NULL; + } + NOKPROBE_SYMBOL(pop_kprobe); + diff --git a/queue-4.14/s390-kprobes-fix-irq-mask-clobbering-on-kprobe-reenter-from-post_handler.patch b/queue-4.14/s390-kprobes-fix-irq-mask-clobbering-on-kprobe-reenter-from-post_handler.patch new file mode 100644 index 00000000000..107098764ac --- /dev/null +++ b/queue-4.14/s390-kprobes-fix-irq-mask-clobbering-on-kprobe-reenter-from-post_handler.patch @@ -0,0 +1,80 @@ +From 42e19e6f04984088b6f9f0507c4c89a8152d9730 Mon Sep 17 00:00:00 2001 +From: Vasily Gorbik +Date: Wed, 1 Mar 2023 02:23:08 +0100 +Subject: s390/kprobes: fix irq mask clobbering on kprobe reenter from post_handler + +From: Vasily Gorbik + +commit 42e19e6f04984088b6f9f0507c4c89a8152d9730 upstream. + +Recent test_kprobe_missed kprobes kunit test uncovers the following error +(reported when CONFIG_DEBUG_ATOMIC_SLEEP is enabled): + +BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580 +in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 662, name: kunit_try_catch +preempt_count: 0, expected: 0 +RCU nest depth: 0, expected: 0 +no locks held by kunit_try_catch/662. +irq event stamp: 280 +hardirqs last enabled at (279): [<00000003e60a3d42>] __do_pgm_check+0x17a/0x1c0 +hardirqs last disabled at (280): [<00000003e3bd774a>] kprobe_exceptions_notify+0x27a/0x318 +softirqs last enabled at (0): [<00000003e3c5c890>] copy_process+0x14a8/0x4c80 +softirqs last disabled at (0): [<0000000000000000>] 0x0 +CPU: 46 PID: 662 Comm: kunit_try_catch Tainted: G N 6.2.0-173644-g44c18d77f0c0 #2 +Hardware name: IBM 3931 A01 704 (LPAR) +Call Trace: + [<00000003e60a3a00>] dump_stack_lvl+0x120/0x198 + [<00000003e3d02e82>] __might_resched+0x60a/0x668 + [<00000003e60b9908>] __mutex_lock+0xc0/0x14e0 + [<00000003e60bad5a>] mutex_lock_nested+0x32/0x40 + [<00000003e3f7b460>] unregister_kprobe+0x30/0xd8 + [<00000003e51b2602>] test_kprobe_missed+0xf2/0x268 + [<00000003e51b5406>] kunit_try_run_case+0x10e/0x290 + [<00000003e51b7dfa>] kunit_generic_run_threadfn_adapter+0x62/0xb8 + [<00000003e3ce30f8>] kthread+0x2d0/0x398 + [<00000003e3b96afa>] __ret_from_fork+0x8a/0xe8 + [<00000003e60ccada>] ret_from_fork+0xa/0x40 + +The reason for this error report is that kprobes handling code failed +to restore irqs. + +The problem is that when kprobe is triggered from another kprobe +post_handler current sequence of enable_singlestep / disable_singlestep +is the following: +enable_singlestep <- original kprobe (saves kprobe_saved_imask) +enable_singlestep <- kprobe triggered from post_handler (clobbers kprobe_saved_imask) +disable_singlestep <- kprobe triggered from post_handler (restores kprobe_saved_imask) +disable_singlestep <- original kprobe (restores wrong clobbered kprobe_saved_imask) + +There is just one kprobe_ctlblk per cpu and both calls saves and +loads irq mask to kprobe_saved_imask. To fix the problem simply move +resume_execution (which calls disable_singlestep) before calling +post_handler. This also fixes the problem that post_handler is called +with pt_regs which were not yet adjusted after single-stepping. + +Cc: stable@vger.kernel.org +Fixes: 4ba069b802c2 ("[S390] add kprobes support.") +Reviewed-by: Heiko Carstens +Signed-off-by: Vasily Gorbik +Signed-off-by: Heiko Carstens +Signed-off-by: Greg Kroah-Hartman +--- + arch/s390/kernel/kprobes.c | 3 +-- + 1 file changed, 1 insertion(+), 2 deletions(-) + +--- a/arch/s390/kernel/kprobes.c ++++ b/arch/s390/kernel/kprobes.c +@@ -546,12 +546,11 @@ static int post_kprobe_handler(struct pt + if (!p) + return 0; + ++ resume_execution(p, regs); + if (kcb->kprobe_status != KPROBE_REENTER && p->post_handler) { + kcb->kprobe_status = KPROBE_HIT_SSDONE; + p->post_handler(p, regs, 0); + } +- +- resume_execution(p, regs); + pop_kprobe(kcb); + preempt_enable_no_resched(); + diff --git a/queue-4.14/series b/queue-4.14/series index 08d83286375..4fee649d3c7 100644 --- a/queue-4.14/series +++ b/queue-4.14/series @@ -99,3 +99,5 @@ dm-cache-add-cond_resched-to-various-workqueue-loops.patch spi-bcm63xx-hsspi-fix-multi-bit-mode-setting.patch wifi-rtl8xxxu-fixing-transmisison-failure-for-rtl8192eu.patch rtc-pm8xxx-fix-set-alarm-race.patch +s390-kprobes-fix-irq-mask-clobbering-on-kprobe-reenter-from-post_handler.patch +s390-kprobes-fix-current_kprobe-never-cleared-after-kprobes-reenter.patch