From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
Enable execmem's cache of PMD_SIZE'ed pages mapped as ROX for module
text allocations.
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
arch/x86/mm/init.c | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index eb503f53c319..a0ec99fb9385 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -1053,6 +1053,15 @@ unsigned long arch_max_swapfile_size(void)
#ifdef CONFIG_EXECMEM
static struct execmem_info execmem_info __ro_after_init;
+static void execmem_fill_trapping_insns(void *ptr, size_t size, bool writeable)
+{
+ /* fill memory with INT3 instructions */
+ if (writeable)
+ memset(ptr, INT3_INSN_OPCODE, size);
+ else
+ text_poke_set(ptr, INT3_INSN_OPCODE, size);
+}
+
struct execmem_info __init *execmem_arch_setup(void)
{
unsigned long start, offset = 0;
@@ -1063,8 +1072,23 @@ struct execmem_info __init *execmem_arch_setup(void)
start = MODULES_VADDR + offset;
execmem_info = (struct execmem_info){
+ .fill_trapping_insns = execmem_fill_trapping_insns,
.ranges = {
- [EXECMEM_DEFAULT] = {
+ [EXECMEM_MODULE_TEXT] = {
+ .flags = EXECMEM_KASAN_SHADOW | EXECMEM_ROX_CACHE,
+ .start = start,
+ .end = MODULES_END,
+ .pgprot = PAGE_KERNEL_ROX,
+ .alignment = MODULE_ALIGN,
+ },
+ [EXECMEM_KPROBES ... EXECMEM_BPF] = {
+ .flags = EXECMEM_KASAN_SHADOW,
+ .start = start,
+ .end = MODULES_END,
+ .pgprot = PAGE_KERNEL,
+ .alignment = MODULE_ALIGN,
+ },
+ [EXECMEM_MODULE_DATA] = {
.flags = EXECMEM_KASAN_SHADOW,
.start = start,
.end = MODULES_END,
--
2.43.0On (24/10/09 21:08), Mike Rapoport wrote: > From: "Mike Rapoport (Microsoft)" <rppt@kernel.org> > > Enable execmem's cache of PMD_SIZE'ed pages mapped as ROX for module > text allocations. > With this modprobe disappoints kmemleak [ 12.700128] kmemleak: Found object by alias at 0xffffffffa000a000 [ 12.702179] CPU: 5 UID: 0 PID: 410 Comm: modprobe Tainted: G N 6.12.0-rc2+ #760 [ 12.704656] Tainted: [N]=TEST [ 12.705526] Call Trace: [ 12.706250] <TASK> [ 12.706888] dump_stack_lvl+0x3e/0xdb [ 12.707961] __find_and_get_object+0x100/0x110 [ 12.709256] kmemleak_no_scan+0x2e/0xb0 [ 12.710354] kmemleak_load_module+0xad/0xe0 [ 12.711557] load_module+0x2391/0x45a0 [ 12.712507] __se_sys_finit_module+0x4e0/0x7a0 [ 12.713599] do_syscall_64+0x54/0xf0 [ 12.714477] ? irqentry_exit_to_user_mode+0x33/0x100 [ 12.715696] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 12.716931] RIP: 0033:0x7fc7af51f059 [ 12.717816] Code: 08 89 e8 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 8f 1d 0d 00 f7 d8 64 89 01 48 [ 12.722324] RSP: 002b:00007ffc1d0b0c18 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 [ 12.724173] RAX: ffffffffffffffda RBX: 00005618a9439b20 RCX: 00007fc7af51f059 [ 12.725884] RDX: 0000000000000000 RSI: 000056187aea098b RDI: 0000000000000003 [ 12.727617] RBP: 0000000000000000 R08: 0000000000000060 R09: 00005618a943af60 [ 12.729361] R10: 0000000000000038 R11: 0000000000000246 R12: 000056187aea098b [ 12.731101] R13: 0000000000040000 R14: 00005618a9439ac0 R15: 0000000000000000 [ 12.732814] </TASK> [ 12.733362] kmemleak: Object 0xffffffffa0000000 (size 2097152): [ 12.734800] kmemleak: comm "modprobe", pid 410, jiffies 4294880489 [ 12.736334] kmemleak: min_count = 2 [ 12.737228] kmemleak: count = 0 [ 12.738043] kmemleak: flags = 0x5 [ 12.738917] kmemleak: checksum = 0 [ 12.739783] kmemleak: backtrace: [ 12.740606] kmemleak_vmalloc+0x29/0xc0 [ 12.741532] kasan_alloc_module_shadow+0xbe/0xe0 [ 12.742649] execmem_vmalloc+0x116/0x220 [ 12.743596] execmem_alloc+0xfb/0x3d0 [ 12.744479] load_module+0x1e84/0x45a0 [ 12.745383] __se_sys_finit_module+0x4e0/0x7a0 [ 12.746452] do_syscall_64+0x54/0xf0 [ 12.747319] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 12.748772] kmemleak: Not scanning unknown object at 0xffffffffa000a000 [ 12.750364] CPU: 5 UID: 0 PID: 410 Comm: modprobe Tainted: G N 6.12.0-rc2+ #760 [ 12.752441] Tainted: [N]=TEST [ 12.753165] Call Trace: [ 12.753760] <TASK> [ 12.754279] dump_stack_lvl+0x3e/0xdb [ 12.755165] kmemleak_load_module+0xad/0xe0 [ 12.756165] load_module+0x2391/0x45a0 [ 12.757068] __se_sys_finit_module+0x4e0/0x7a0 [ 12.758135] do_syscall_64+0x54/0xf0 [ 12.759099] ? irqentry_exit_to_user_mode+0x33/0x100 [ 12.760292] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 12.761508] RIP: 0033:0x7fc7af51f059 [ 12.762372] Code: 08 89 e8 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 8f 1d 0d 00 f7 d8 64 89 01 48 [ 12.772361] RSP: 002b:00007ffc1d0b0c18 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 [ 12.774957] RAX: ffffffffffffffda RBX: 00005618a9439b20 RCX: 00007fc7af51f059 [ 12.776635] RDX: 0000000000000000 RSI: 000056187aea098b RDI: 0000000000000003 [ 12.778283] RBP: 0000000000000000 R08: 0000000000000060 R09: 00005618a943af60 [ 12.779949] R10: 0000000000000038 R11: 0000000000000246 R12: 000056187aea098b [ 12.781619] R13: 0000000000040000 R14: 00005618a9439ac0 R15: 0000000000000000 [ 12.783319] </TASK>
On Thu, Oct 10, 2024 at 05:30:33PM +0900, Sergey Senozhatsky wrote:
> On (24/10/09 21:08), Mike Rapoport wrote:
> > From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
> >
> > Enable execmem's cache of PMD_SIZE'ed pages mapped as ROX for module
> > text allocations.
> >
>
> With this modprobe disappoints kmemleak
>
> [ 12.700128] kmemleak: Found object by alias at 0xffffffffa000a000
> [ 12.702179] CPU: 5 UID: 0 PID: 410 Comm: modprobe Tainted: G N 6.12.0-rc2+ #760
> [ 12.704656] Tainted: [N]=TEST
> [ 12.705526] Call Trace:
> [ 12.706250] <TASK>
> [ 12.706888] dump_stack_lvl+0x3e/0xdb
> [ 12.707961] __find_and_get_object+0x100/0x110
> [ 12.709256] kmemleak_no_scan+0x2e/0xb0
> [ 12.710354] kmemleak_load_module+0xad/0xe0
> [ 12.711557] load_module+0x2391/0x45a0
> [ 12.712507] __se_sys_finit_module+0x4e0/0x7a0
> [ 12.713599] do_syscall_64+0x54/0xf0
> [ 12.714477] ? irqentry_exit_to_user_mode+0x33/0x100
> [ 12.715696] entry_SYSCALL_64_after_hwframe+0x4b/0x53
> [ 12.716931] RIP: 0033:0x7fc7af51f059
> [ 12.717816] Code: 08 89 e8 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 8f 1d 0d 00 f7 d8 64 89 01 48
> [ 12.722324] RSP: 002b:00007ffc1d0b0c18 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
> [ 12.724173] RAX: ffffffffffffffda RBX: 00005618a9439b20 RCX: 00007fc7af51f059
> [ 12.725884] RDX: 0000000000000000 RSI: 000056187aea098b RDI: 0000000000000003
> [ 12.727617] RBP: 0000000000000000 R08: 0000000000000060 R09: 00005618a943af60
> [ 12.729361] R10: 0000000000000038 R11: 0000000000000246 R12: 000056187aea098b
> [ 12.731101] R13: 0000000000040000 R14: 00005618a9439ac0 R15: 0000000000000000
> [ 12.732814] </TASK>
Below is a quick fix, I'll revisit module - kmemleak interaction in v6
diff --git a/kernel/module/debug_kmemleak.c b/kernel/module/debug_kmemleak.c
index b4cc03842d70..df873dad049d 100644
--- a/kernel/module/debug_kmemleak.c
+++ b/kernel/module/debug_kmemleak.c
@@ -14,7 +14,8 @@ void kmemleak_load_module(const struct module *mod,
{
/* only scan writable, non-executable sections */
for_each_mod_mem_type(type) {
- if (type != MOD_DATA && type != MOD_INIT_DATA)
+ if (type != MOD_DATA && type != MOD_INIT_DATA &&
+ !mod->mem[type].is_rox)
kmemleak_no_scan(mod->mem[type].base);
}
}
--
Sincerely yours,
Mike.
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