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Thu, 13 Oct 2022 23:08:01 -0700 (PDT) MIME-Version: 1.0 References: <20221007234315.2877365-1-song@kernel.org> <20221007234315.2877365-4-song@kernel.org> In-Reply-To: From: Song Liu Date: Thu, 13 Oct 2022 23:07:49 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC v2 3/4] modules, x86: use vmalloc_exec for module core To: Aaron Lu Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, x86@kernel.org, peterz@infradead.org, hch@lst.de, kernel-team@fb.com, rick.p.edgecombe@intel.com, dave.hansen@intel.com, urezki@gmail.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 13, 2022 at 8:49 PM Aaron Lu wrote: > > On Fri, Oct 07, 2022 at 04:43:14PM -0700, Song Liu wrote: > > This is a prototype that allows modules to share 2MB text pages with other > > modules and BPF programs. > > > > Current version only covers core_layout. > > --- > > arch/x86/Kconfig | 1 + > > arch/x86/kernel/alternative.c | 30 ++++++++++++++++++++++++------ > > arch/x86/kernel/module.c | 1 + > > kernel/module/main.c | 23 +++++++++++++---------- > > kernel/module/strict_rwx.c | 3 --- > > kernel/trace/ftrace.c | 3 ++- > > 6 files changed, 41 insertions(+), 20 deletions(-) > > > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > > index f9920f1341c8..0b1ea05a1da6 100644 > > --- a/arch/x86/Kconfig > > +++ b/arch/x86/Kconfig > > @@ -91,6 +91,7 @@ config X86 > > select ARCH_HAS_SET_DIRECT_MAP > > select ARCH_HAS_STRICT_KERNEL_RWX > > select ARCH_HAS_STRICT_MODULE_RWX > > + select ARCH_WANTS_MODULES_DATA_IN_VMALLOC if X86_64 > > select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE > > select ARCH_HAS_SYSCALL_WRAPPER > > select ARCH_HAS_UBSAN_SANITIZE_ALL > > diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c > > index 4f3204364caa..0e47a558c5bc 100644 > > --- a/arch/x86/kernel/alternative.c > > +++ b/arch/x86/kernel/alternative.c > > @@ -332,7 +332,13 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start, > > > > DUMP_BYTES(insn_buff, insn_buff_sz, "%px: final_insn: ", instr); > > > > - text_poke_early(instr, insn_buff, insn_buff_sz); > > + if (system_state < SYSTEM_RUNNING) { > > + text_poke_early(instr, insn_buff, insn_buff_sz); > > + } else { > > + mutex_lock(&text_mutex); > > + text_poke(instr, insn_buff, insn_buff_sz); > > + mutex_unlock(&text_mutex); > > + } > > > > next: > > optimize_nops(instr, a->instrlen); > > @@ -503,7 +509,13 @@ void __init_or_module noinline apply_retpolines(s32 *start, s32 *end) > > optimize_nops(bytes, len); > > DUMP_BYTES(((u8*)addr), len, "%px: orig: ", addr); > > DUMP_BYTES(((u8*)bytes), len, "%px: repl: ", addr); > > - text_poke_early(addr, bytes, len); > > + if (system_state == SYSTEM_BOOTING) { > > + text_poke_early(addr, bytes, len); > > + } else { > > + mutex_lock(&text_mutex); > > + text_poke(addr, bytes, len); > > + mutex_unlock(&text_mutex); > > + } > > } > > } > > } > > @@ -568,7 +580,13 @@ void __init_or_module noinline apply_returns(s32 *start, s32 *end) > > if (len == insn.length) { > > DUMP_BYTES(((u8*)addr), len, "%px: orig: ", addr); > > DUMP_BYTES(((u8*)bytes), len, "%px: repl: ", addr); > > - text_poke_early(addr, bytes, len); > > + if (unlikely(system_state == SYSTEM_BOOTING)) { > > + text_poke_early(addr, bytes, len); > > + } else { > > + mutex_lock(&text_mutex); > > + text_poke(addr, bytes, len); > > + mutex_unlock(&text_mutex); > > + } > > } > > } > > } > > @@ -609,7 +627,7 @@ void __init_or_module noinline apply_ibt_endbr(s32 *start, s32 *end) > > */ > > DUMP_BYTES(((u8*)addr), 4, "%px: orig: ", addr); > > DUMP_BYTES(((u8*)&poison), 4, "%px: repl: ", addr); > > - text_poke_early(addr, &poison, 4); > > + text_poke(addr, &poison, 4); > > } > > } > > > > @@ -791,7 +809,7 @@ void __init_or_module apply_paravirt(struct paravirt_patch_site *start, > > > > /* Pad the rest with nops */ > > add_nops(insn_buff + used, p->len - used); > > - text_poke_early(p->instr, insn_buff, p->len); > > + text_poke(p->instr, insn_buff, p->len); > > Got below warning when booting a VM: > > [ 0.190098] ------------[ cut here ]------------ > [ 0.190377] WARNING: CPU: 0 PID: 0 at /home/aaron/linux/src/arch/x86/kernel/alternative.c:1224 text_poke+0x53/0x60 > [ 0.191083] Modules linked in: > [ 0.191269] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.0.0-00004-gc49d19177d78 #5 > [ 0.191721] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 > [ 0.192083] RIP: 0010:text_poke+0x53/0x60 > [ 0.192326] Code: c7 c7 20 e7 02 81 5b 5d e9 2a f8 ff ff be ff ff ff ff 48 c7 c7 b0 6d 06 83 48 89 14 24 e8 75 fd bf 00 85 c0 48 8b 14 24 75 c8 <0f> 0b eb c4 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 57 41 56 > [ 0.193083] RSP: 0000:ffffffff83003d60 EFLAGS: 00010246 > [ 0.194083] RAX: 0000000000000000 RBX: ffffffff810295b7 RCX: 0000000000000001 > [ 0.194506] RDX: 0000000000000006 RSI: ffffffff828b01c5 RDI: ffffffff8293898e > [ 0.195083] RBP: ffffffff83003d82 R08: ffffffff82206520 R09: 0000000000000001 > [ 0.195506] R10: 0000000000000000 R11: 0000000000000001 R12: ffffffff8a9949c0 > [ 0.195929] R13: ffffffff8a95f400 R14: 00000000ffffffff R15: 00000000ffffffff > [ 0.196083] FS: 0000000000000000(0000) GS:ffff88842de00000(0000) knlGS:0000000000000000 > [ 0.196562] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 0.197083] CR2: ffff88843ffff000 CR3: 0000000003012001 CR4: 0000000000770ef0 > [ 0.197508] PKRU: 55555554 > [ 0.197673] Call Trace: > [ 0.197822] > [ 0.198084] apply_paravirt+0xaf/0x150 > [ 0.198313] ? __might_resched+0x3f/0x280 > [ 0.198557] ? synchronize_rcu+0xe0/0x1c0 > [ 0.198799] ? lock_release+0x230/0x450 > [ 0.199030] ? _raw_spin_unlock_irqrestore+0x30/0x60 > [ 0.199083] ? lockdep_hardirqs_on+0x79/0x100 > [ 0.199345] ? _raw_spin_unlock_irqrestore+0x3b/0x60 > [ 0.199643] ? atomic_notifier_chain_unregister+0x51/0x80 > [ 0.200084] alternative_instructions+0x27/0xfa > [ 0.200357] check_bugs+0xe08/0xe82 > [ 0.200570] start_kernel+0x692/0x6cc > [ 0.200797] secondary_startup_64_no_verify+0xe0/0xeb > [ 0.201088] > [ 0.201223] irq event stamp: 13575 > [ 0.201428] hardirqs last enabled at (13583): [] __up_console_sem+0x52/0x60 > [ 0.202083] hardirqs last disabled at (13592): [] __up_console_sem+0x37/0x60 > [ 0.202594] softirqs last enabled at (12762): [] cgroup_idr_alloc.constprop.60+0x59/0x100 > [ 0.203083] softirqs last disabled at (12750): [] cgroup_idr_alloc.constprop.60+0x2d/0x100 > [ 0.203665] ---[ end trace 0000000000000000 ]--- > > Looks like it is also necessary to differentiate system_state in > apply_paravirt() like you did in the other apply_XXX() functions. Thanks for the report! Somehow I didn't see this in my qemu vm. Song