85 lines
3.3 KiB
Diff
85 lines
3.3 KiB
Diff
From b55d483e29d60df8474df1967ca72fe18677650d Mon Sep 17 00:00:00 2001
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Message-Id: <b55d483e29d60df8474df1967ca72fe18677650d.1601675152.git.zanussi@kernel.org>
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In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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From: Yong Zhang <yong.zhang0@gmail.com>
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Date: Tue, 15 May 2012 13:53:56 +0800
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Subject: [PATCH 170/333] mm: Protect activate_mm() by
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preempt_[disable&enable]_rt()
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz
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User preempt_*_rt instead of local_irq_*_rt or otherwise there will be
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warning on ARM like below:
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WARNING: at build/linux/kernel/smp.c:459 smp_call_function_many+0x98/0x264()
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Modules linked in:
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[<c0013bb4>] (unwind_backtrace+0x0/0xe4) from [<c001be94>] (warn_slowpath_common+0x4c/0x64)
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[<c001be94>] (warn_slowpath_common+0x4c/0x64) from [<c001bec4>] (warn_slowpath_null+0x18/0x1c)
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[<c001bec4>] (warn_slowpath_null+0x18/0x1c) from [<c0053ff8>](smp_call_function_many+0x98/0x264)
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[<c0053ff8>] (smp_call_function_many+0x98/0x264) from [<c0054364>] (smp_call_function+0x44/0x6c)
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[<c0054364>] (smp_call_function+0x44/0x6c) from [<c0017d50>] (__new_context+0xbc/0x124)
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[<c0017d50>] (__new_context+0xbc/0x124) from [<c009e49c>] (flush_old_exec+0x460/0x5e4)
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[<c009e49c>] (flush_old_exec+0x460/0x5e4) from [<c00d61ac>] (load_elf_binary+0x2e0/0x11ac)
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[<c00d61ac>] (load_elf_binary+0x2e0/0x11ac) from [<c009d060>] (search_binary_handler+0x94/0x2a4)
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[<c009d060>] (search_binary_handler+0x94/0x2a4) from [<c009e8fc>] (do_execve+0x254/0x364)
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[<c009e8fc>] (do_execve+0x254/0x364) from [<c0010e84>] (sys_execve+0x34/0x54)
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[<c0010e84>] (sys_execve+0x34/0x54) from [<c000da00>] (ret_fast_syscall+0x0/0x30)
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---[ end trace 0000000000000002 ]---
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The reason is that ARM need irq enabled when doing activate_mm().
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According to mm-protect-activate-switch-mm.patch, actually
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preempt_[disable|enable]_rt() is sufficient.
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Inspired-by: Steven Rostedt <rostedt@goodmis.org>
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Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
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Cc: Steven Rostedt <rostedt@goodmis.org>
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Link: http://lkml.kernel.org/r/1337061236-1766-1-git-send-email-yong.zhang0@gmail.com
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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fs/exec.c | 2 ++
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mm/mmu_context.c | 2 ++
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2 files changed, 4 insertions(+)
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diff --git a/fs/exec.c b/fs/exec.c
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index cece8c14f377..1941f39a3453 100644
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--- a/fs/exec.c
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+++ b/fs/exec.c
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@@ -1028,12 +1028,14 @@ static int exec_mmap(struct mm_struct *mm)
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}
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}
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task_lock(tsk);
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+ preempt_disable_rt();
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active_mm = tsk->active_mm;
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tsk->mm = mm;
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tsk->active_mm = mm;
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activate_mm(active_mm, mm);
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tsk->mm->vmacache_seqnum = 0;
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vmacache_flush(tsk);
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+ preempt_enable_rt();
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task_unlock(tsk);
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if (old_mm) {
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up_read(&old_mm->mmap_sem);
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diff --git a/mm/mmu_context.c b/mm/mmu_context.c
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index 3e612ae748e9..d0ccc070979f 100644
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--- a/mm/mmu_context.c
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+++ b/mm/mmu_context.c
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@@ -25,6 +25,7 @@ void use_mm(struct mm_struct *mm)
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struct task_struct *tsk = current;
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task_lock(tsk);
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+ preempt_disable_rt();
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active_mm = tsk->active_mm;
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if (active_mm != mm) {
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mmgrab(mm);
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@@ -32,6 +33,7 @@ void use_mm(struct mm_struct *mm)
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}
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tsk->mm = mm;
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switch_mm(active_mm, mm, tsk);
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+ preempt_enable_rt();
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task_unlock(tsk);
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#ifdef finish_arch_post_lock_switch
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finish_arch_post_lock_switch();
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--
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2.17.1
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