mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-24 17:59:32 +00:00
![Chen Zhongjin](/assets/img/avatar_default.png)
[ Upstream commit230db82413
] When a console stack dump is initiated with CONFIG_GCOV_PROFILE_ALL enabled, show_trace_log_lvl() gets out of sync with the ORC unwinder, causing the stack trace to show all text addresses as unreliable: # echo l > /proc/sysrq-trigger [ 477.521031] sysrq: Show backtrace of all active CPUs [ 477.523813] NMI backtrace for cpu 0 [ 477.524492] CPU: 0 PID: 1021 Comm: bash Not tainted 6.0.0 #65 [ 477.525295] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.0-1.fc36 04/01/2014 [ 477.526439] Call Trace: [ 477.526854] <TASK> [ 477.527216] ? dump_stack_lvl+0xc7/0x114 [ 477.527801] ? dump_stack+0x13/0x1f [ 477.528331] ? nmi_cpu_backtrace.cold+0xb5/0x10d [ 477.528998] ? lapic_can_unplug_cpu+0xa0/0xa0 [ 477.529641] ? nmi_trigger_cpumask_backtrace+0x16a/0x1f0 [ 477.530393] ? arch_trigger_cpumask_backtrace+0x1d/0x30 [ 477.531136] ? sysrq_handle_showallcpus+0x1b/0x30 [ 477.531818] ? __handle_sysrq.cold+0x4e/0x1ae [ 477.532451] ? write_sysrq_trigger+0x63/0x80 [ 477.533080] ? proc_reg_write+0x92/0x110 [ 477.533663] ? vfs_write+0x174/0x530 [ 477.534265] ? handle_mm_fault+0x16f/0x500 [ 477.534940] ? ksys_write+0x7b/0x170 [ 477.535543] ? __x64_sys_write+0x1d/0x30 [ 477.536191] ? do_syscall_64+0x6b/0x100 [ 477.536809] ? entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 477.537609] </TASK> This happens when the compiled code for show_stack() has a single word on the stack, and doesn't use a tail call to show_stack_log_lvl(). (CONFIG_GCOV_PROFILE_ALL=y is the only known case of this.) Then the __unwind_start() skip logic hits an off-by-one bug and fails to unwind all the way to the intended starting frame. Fix it by reverting the following commit:f1d9a2abff
("x86/unwind/orc: Don't skip the first frame for inactive tasks") The original justification for that commit no longer exists. That original issue was later fixed in a different way, with the following commit:f2ac57a4c4
("x86/unwind/orc: Fix inactive tasks with stack pointer in %sp on GCC 10 compiled kernels") Fixes:f1d9a2abff
("x86/unwind/orc: Don't skip the first frame for inactive tasks") Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com> [jpoimboe: rewrite commit log] Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
700 lines
18 KiB
C
700 lines
18 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
#include <linux/module.h>
|
|
#include <linux/sort.h>
|
|
#include <asm/ptrace.h>
|
|
#include <asm/stacktrace.h>
|
|
#include <asm/unwind.h>
|
|
#include <asm/orc_types.h>
|
|
#include <asm/orc_lookup.h>
|
|
|
|
#define orc_warn(fmt, ...) \
|
|
printk_deferred_once(KERN_WARNING pr_fmt("WARNING: " fmt), ##__VA_ARGS__)
|
|
|
|
extern int __start_orc_unwind_ip[];
|
|
extern int __stop_orc_unwind_ip[];
|
|
extern struct orc_entry __start_orc_unwind[];
|
|
extern struct orc_entry __stop_orc_unwind[];
|
|
|
|
static DEFINE_MUTEX(sort_mutex);
|
|
int *cur_orc_ip_table = __start_orc_unwind_ip;
|
|
struct orc_entry *cur_orc_table = __start_orc_unwind;
|
|
|
|
unsigned int lookup_num_blocks;
|
|
bool orc_init;
|
|
|
|
static inline unsigned long orc_ip(const int *ip)
|
|
{
|
|
return (unsigned long)ip + *ip;
|
|
}
|
|
|
|
static struct orc_entry *__orc_find(int *ip_table, struct orc_entry *u_table,
|
|
unsigned int num_entries, unsigned long ip)
|
|
{
|
|
int *first = ip_table;
|
|
int *last = ip_table + num_entries - 1;
|
|
int *mid = first, *found = first;
|
|
|
|
if (!num_entries)
|
|
return NULL;
|
|
|
|
/*
|
|
* Do a binary range search to find the rightmost duplicate of a given
|
|
* starting address. Some entries are section terminators which are
|
|
* "weak" entries for ensuring there are no gaps. They should be
|
|
* ignored when they conflict with a real entry.
|
|
*/
|
|
while (first <= last) {
|
|
mid = first + ((last - first) / 2);
|
|
|
|
if (orc_ip(mid) <= ip) {
|
|
found = mid;
|
|
first = mid + 1;
|
|
} else
|
|
last = mid - 1;
|
|
}
|
|
|
|
return u_table + (found - ip_table);
|
|
}
|
|
|
|
#ifdef CONFIG_MODULES
|
|
static struct orc_entry *orc_module_find(unsigned long ip)
|
|
{
|
|
struct module *mod;
|
|
|
|
mod = __module_address(ip);
|
|
if (!mod || !mod->arch.orc_unwind || !mod->arch.orc_unwind_ip)
|
|
return NULL;
|
|
return __orc_find(mod->arch.orc_unwind_ip, mod->arch.orc_unwind,
|
|
mod->arch.num_orcs, ip);
|
|
}
|
|
#else
|
|
static struct orc_entry *orc_module_find(unsigned long ip)
|
|
{
|
|
return NULL;
|
|
}
|
|
#endif
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE
|
|
static struct orc_entry *orc_find(unsigned long ip);
|
|
|
|
/*
|
|
* Ftrace dynamic trampolines do not have orc entries of their own.
|
|
* But they are copies of the ftrace entries that are static and
|
|
* defined in ftrace_*.S, which do have orc entries.
|
|
*
|
|
* If the unwinder comes across a ftrace trampoline, then find the
|
|
* ftrace function that was used to create it, and use that ftrace
|
|
* function's orc entry, as the placement of the return code in
|
|
* the stack will be identical.
|
|
*/
|
|
static struct orc_entry *orc_ftrace_find(unsigned long ip)
|
|
{
|
|
struct ftrace_ops *ops;
|
|
unsigned long tramp_addr, offset;
|
|
|
|
ops = ftrace_ops_trampoline(ip);
|
|
if (!ops)
|
|
return NULL;
|
|
|
|
/* Set tramp_addr to the start of the code copied by the trampoline */
|
|
if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
|
|
tramp_addr = (unsigned long)ftrace_regs_caller;
|
|
else
|
|
tramp_addr = (unsigned long)ftrace_caller;
|
|
|
|
/* Now place tramp_addr to the location within the trampoline ip is at */
|
|
offset = ip - ops->trampoline;
|
|
tramp_addr += offset;
|
|
|
|
/* Prevent unlikely recursion */
|
|
if (ip == tramp_addr)
|
|
return NULL;
|
|
|
|
return orc_find(tramp_addr);
|
|
}
|
|
#else
|
|
static struct orc_entry *orc_ftrace_find(unsigned long ip)
|
|
{
|
|
return NULL;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* If we crash with IP==0, the last successfully executed instruction
|
|
* was probably an indirect function call with a NULL function pointer,
|
|
* and we don't have unwind information for NULL.
|
|
* This hardcoded ORC entry for IP==0 allows us to unwind from a NULL function
|
|
* pointer into its parent and then continue normally from there.
|
|
*/
|
|
static struct orc_entry null_orc_entry = {
|
|
.sp_offset = sizeof(long),
|
|
.sp_reg = ORC_REG_SP,
|
|
.bp_reg = ORC_REG_UNDEFINED,
|
|
.type = ORC_TYPE_CALL
|
|
};
|
|
|
|
/* Fake frame pointer entry -- used as a fallback for generated code */
|
|
static struct orc_entry orc_fp_entry = {
|
|
.type = ORC_TYPE_CALL,
|
|
.sp_reg = ORC_REG_BP,
|
|
.sp_offset = 16,
|
|
.bp_reg = ORC_REG_PREV_SP,
|
|
.bp_offset = -16,
|
|
.end = 0,
|
|
};
|
|
|
|
static struct orc_entry *orc_find(unsigned long ip)
|
|
{
|
|
static struct orc_entry *orc;
|
|
|
|
if (ip == 0)
|
|
return &null_orc_entry;
|
|
|
|
/* For non-init vmlinux addresses, use the fast lookup table: */
|
|
if (ip >= LOOKUP_START_IP && ip < LOOKUP_STOP_IP) {
|
|
unsigned int idx, start, stop;
|
|
|
|
idx = (ip - LOOKUP_START_IP) / LOOKUP_BLOCK_SIZE;
|
|
|
|
if (unlikely((idx >= lookup_num_blocks-1))) {
|
|
orc_warn("WARNING: bad lookup idx: idx=%u num=%u ip=%pB\n",
|
|
idx, lookup_num_blocks, (void *)ip);
|
|
return NULL;
|
|
}
|
|
|
|
start = orc_lookup[idx];
|
|
stop = orc_lookup[idx + 1] + 1;
|
|
|
|
if (unlikely((__start_orc_unwind + start >= __stop_orc_unwind) ||
|
|
(__start_orc_unwind + stop > __stop_orc_unwind))) {
|
|
orc_warn("WARNING: bad lookup value: idx=%u num=%u start=%u stop=%u ip=%pB\n",
|
|
idx, lookup_num_blocks, start, stop, (void *)ip);
|
|
return NULL;
|
|
}
|
|
|
|
return __orc_find(__start_orc_unwind_ip + start,
|
|
__start_orc_unwind + start, stop - start, ip);
|
|
}
|
|
|
|
/* vmlinux .init slow lookup: */
|
|
if (init_kernel_text(ip))
|
|
return __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
|
|
__stop_orc_unwind_ip - __start_orc_unwind_ip, ip);
|
|
|
|
/* Module lookup: */
|
|
orc = orc_module_find(ip);
|
|
if (orc)
|
|
return orc;
|
|
|
|
return orc_ftrace_find(ip);
|
|
}
|
|
|
|
static void orc_sort_swap(void *_a, void *_b, int size)
|
|
{
|
|
struct orc_entry *orc_a, *orc_b;
|
|
struct orc_entry orc_tmp;
|
|
int *a = _a, *b = _b, tmp;
|
|
int delta = _b - _a;
|
|
|
|
/* Swap the .orc_unwind_ip entries: */
|
|
tmp = *a;
|
|
*a = *b + delta;
|
|
*b = tmp - delta;
|
|
|
|
/* Swap the corresponding .orc_unwind entries: */
|
|
orc_a = cur_orc_table + (a - cur_orc_ip_table);
|
|
orc_b = cur_orc_table + (b - cur_orc_ip_table);
|
|
orc_tmp = *orc_a;
|
|
*orc_a = *orc_b;
|
|
*orc_b = orc_tmp;
|
|
}
|
|
|
|
static int orc_sort_cmp(const void *_a, const void *_b)
|
|
{
|
|
struct orc_entry *orc_a;
|
|
const int *a = _a, *b = _b;
|
|
unsigned long a_val = orc_ip(a);
|
|
unsigned long b_val = orc_ip(b);
|
|
|
|
if (a_val > b_val)
|
|
return 1;
|
|
if (a_val < b_val)
|
|
return -1;
|
|
|
|
/*
|
|
* The "weak" section terminator entries need to always be on the left
|
|
* to ensure the lookup code skips them in favor of real entries.
|
|
* These terminator entries exist to handle any gaps created by
|
|
* whitelisted .o files which didn't get objtool generation.
|
|
*/
|
|
orc_a = cur_orc_table + (a - cur_orc_ip_table);
|
|
return orc_a->sp_reg == ORC_REG_UNDEFINED && !orc_a->end ? -1 : 1;
|
|
}
|
|
|
|
#ifdef CONFIG_MODULES
|
|
void unwind_module_init(struct module *mod, void *_orc_ip, size_t orc_ip_size,
|
|
void *_orc, size_t orc_size)
|
|
{
|
|
int *orc_ip = _orc_ip;
|
|
struct orc_entry *orc = _orc;
|
|
unsigned int num_entries = orc_ip_size / sizeof(int);
|
|
|
|
WARN_ON_ONCE(orc_ip_size % sizeof(int) != 0 ||
|
|
orc_size % sizeof(*orc) != 0 ||
|
|
num_entries != orc_size / sizeof(*orc));
|
|
|
|
/*
|
|
* The 'cur_orc_*' globals allow the orc_sort_swap() callback to
|
|
* associate an .orc_unwind_ip table entry with its corresponding
|
|
* .orc_unwind entry so they can both be swapped.
|
|
*/
|
|
mutex_lock(&sort_mutex);
|
|
cur_orc_ip_table = orc_ip;
|
|
cur_orc_table = orc;
|
|
sort(orc_ip, num_entries, sizeof(int), orc_sort_cmp, orc_sort_swap);
|
|
mutex_unlock(&sort_mutex);
|
|
|
|
mod->arch.orc_unwind_ip = orc_ip;
|
|
mod->arch.orc_unwind = orc;
|
|
mod->arch.num_orcs = num_entries;
|
|
}
|
|
#endif
|
|
|
|
void __init unwind_init(void)
|
|
{
|
|
size_t orc_ip_size = (void *)__stop_orc_unwind_ip - (void *)__start_orc_unwind_ip;
|
|
size_t orc_size = (void *)__stop_orc_unwind - (void *)__start_orc_unwind;
|
|
size_t num_entries = orc_ip_size / sizeof(int);
|
|
struct orc_entry *orc;
|
|
int i;
|
|
|
|
if (!num_entries || orc_ip_size % sizeof(int) != 0 ||
|
|
orc_size % sizeof(struct orc_entry) != 0 ||
|
|
num_entries != orc_size / sizeof(struct orc_entry)) {
|
|
orc_warn("WARNING: Bad or missing .orc_unwind table. Disabling unwinder.\n");
|
|
return;
|
|
}
|
|
|
|
/* Sort the .orc_unwind and .orc_unwind_ip tables: */
|
|
sort(__start_orc_unwind_ip, num_entries, sizeof(int), orc_sort_cmp,
|
|
orc_sort_swap);
|
|
|
|
/* Initialize the fast lookup table: */
|
|
lookup_num_blocks = orc_lookup_end - orc_lookup;
|
|
for (i = 0; i < lookup_num_blocks-1; i++) {
|
|
orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
|
|
num_entries,
|
|
LOOKUP_START_IP + (LOOKUP_BLOCK_SIZE * i));
|
|
if (!orc) {
|
|
orc_warn("WARNING: Corrupt .orc_unwind table. Disabling unwinder.\n");
|
|
return;
|
|
}
|
|
|
|
orc_lookup[i] = orc - __start_orc_unwind;
|
|
}
|
|
|
|
/* Initialize the ending block: */
|
|
orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind, num_entries,
|
|
LOOKUP_STOP_IP);
|
|
if (!orc) {
|
|
orc_warn("WARNING: Corrupt .orc_unwind table. Disabling unwinder.\n");
|
|
return;
|
|
}
|
|
orc_lookup[lookup_num_blocks-1] = orc - __start_orc_unwind;
|
|
|
|
orc_init = true;
|
|
}
|
|
|
|
unsigned long unwind_get_return_address(struct unwind_state *state)
|
|
{
|
|
if (unwind_done(state))
|
|
return 0;
|
|
|
|
return __kernel_text_address(state->ip) ? state->ip : 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(unwind_get_return_address);
|
|
|
|
unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
|
|
{
|
|
if (unwind_done(state))
|
|
return NULL;
|
|
|
|
if (state->regs)
|
|
return &state->regs->ip;
|
|
|
|
if (state->sp)
|
|
return (unsigned long *)state->sp - 1;
|
|
|
|
return NULL;
|
|
}
|
|
|
|
static bool stack_access_ok(struct unwind_state *state, unsigned long _addr,
|
|
size_t len)
|
|
{
|
|
struct stack_info *info = &state->stack_info;
|
|
void *addr = (void *)_addr;
|
|
|
|
if (!on_stack(info, addr, len) &&
|
|
(get_stack_info(addr, state->task, info, &state->stack_mask)))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
static bool deref_stack_reg(struct unwind_state *state, unsigned long addr,
|
|
unsigned long *val)
|
|
{
|
|
if (!stack_access_ok(state, addr, sizeof(long)))
|
|
return false;
|
|
|
|
*val = READ_ONCE_NOCHECK(*(unsigned long *)addr);
|
|
return true;
|
|
}
|
|
|
|
static bool deref_stack_regs(struct unwind_state *state, unsigned long addr,
|
|
unsigned long *ip, unsigned long *sp)
|
|
{
|
|
struct pt_regs *regs = (struct pt_regs *)addr;
|
|
|
|
/* x86-32 support will be more complicated due to the ®s->sp hack */
|
|
BUILD_BUG_ON(IS_ENABLED(CONFIG_X86_32));
|
|
|
|
if (!stack_access_ok(state, addr, sizeof(struct pt_regs)))
|
|
return false;
|
|
|
|
*ip = READ_ONCE_NOCHECK(regs->ip);
|
|
*sp = READ_ONCE_NOCHECK(regs->sp);
|
|
return true;
|
|
}
|
|
|
|
static bool deref_stack_iret_regs(struct unwind_state *state, unsigned long addr,
|
|
unsigned long *ip, unsigned long *sp)
|
|
{
|
|
struct pt_regs *regs = (void *)addr - IRET_FRAME_OFFSET;
|
|
|
|
if (!stack_access_ok(state, addr, IRET_FRAME_SIZE))
|
|
return false;
|
|
|
|
*ip = READ_ONCE_NOCHECK(regs->ip);
|
|
*sp = READ_ONCE_NOCHECK(regs->sp);
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* If state->regs is non-NULL, and points to a full pt_regs, just get the reg
|
|
* value from state->regs.
|
|
*
|
|
* Otherwise, if state->regs just points to IRET regs, and the previous frame
|
|
* had full regs, it's safe to get the value from the previous regs. This can
|
|
* happen when early/late IRQ entry code gets interrupted by an NMI.
|
|
*/
|
|
static bool get_reg(struct unwind_state *state, unsigned int reg_off,
|
|
unsigned long *val)
|
|
{
|
|
unsigned int reg = reg_off/8;
|
|
|
|
if (!state->regs)
|
|
return false;
|
|
|
|
if (state->full_regs) {
|
|
*val = READ_ONCE_NOCHECK(((unsigned long *)state->regs)[reg]);
|
|
return true;
|
|
}
|
|
|
|
if (state->prev_regs) {
|
|
*val = READ_ONCE_NOCHECK(((unsigned long *)state->prev_regs)[reg]);
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
bool unwind_next_frame(struct unwind_state *state)
|
|
{
|
|
unsigned long ip_p, sp, tmp, orig_ip = state->ip, prev_sp = state->sp;
|
|
enum stack_type prev_type = state->stack_info.type;
|
|
struct orc_entry *orc;
|
|
bool indirect = false;
|
|
|
|
if (unwind_done(state))
|
|
return false;
|
|
|
|
/* Don't let modules unload while we're reading their ORC data. */
|
|
preempt_disable();
|
|
|
|
/* End-of-stack check for user tasks: */
|
|
if (state->regs && user_mode(state->regs))
|
|
goto the_end;
|
|
|
|
/*
|
|
* Find the orc_entry associated with the text address.
|
|
*
|
|
* For a call frame (as opposed to a signal frame), state->ip points to
|
|
* the instruction after the call. That instruction's stack layout
|
|
* could be different from the call instruction's layout, for example
|
|
* if the call was to a noreturn function. So get the ORC data for the
|
|
* call instruction itself.
|
|
*/
|
|
orc = orc_find(state->signal ? state->ip : state->ip - 1);
|
|
if (!orc) {
|
|
/*
|
|
* As a fallback, try to assume this code uses a frame pointer.
|
|
* This is useful for generated code, like BPF, which ORC
|
|
* doesn't know about. This is just a guess, so the rest of
|
|
* the unwind is no longer considered reliable.
|
|
*/
|
|
orc = &orc_fp_entry;
|
|
state->error = true;
|
|
}
|
|
|
|
/* End-of-stack check for kernel threads: */
|
|
if (orc->sp_reg == ORC_REG_UNDEFINED) {
|
|
if (!orc->end)
|
|
goto err;
|
|
|
|
goto the_end;
|
|
}
|
|
|
|
/* Find the previous frame's stack: */
|
|
switch (orc->sp_reg) {
|
|
case ORC_REG_SP:
|
|
sp = state->sp + orc->sp_offset;
|
|
break;
|
|
|
|
case ORC_REG_BP:
|
|
sp = state->bp + orc->sp_offset;
|
|
break;
|
|
|
|
case ORC_REG_SP_INDIRECT:
|
|
sp = state->sp + orc->sp_offset;
|
|
indirect = true;
|
|
break;
|
|
|
|
case ORC_REG_BP_INDIRECT:
|
|
sp = state->bp + orc->sp_offset;
|
|
indirect = true;
|
|
break;
|
|
|
|
case ORC_REG_R10:
|
|
if (!get_reg(state, offsetof(struct pt_regs, r10), &sp)) {
|
|
orc_warn("missing regs for base reg R10 at ip %pB\n",
|
|
(void *)state->ip);
|
|
goto err;
|
|
}
|
|
break;
|
|
|
|
case ORC_REG_R13:
|
|
if (!get_reg(state, offsetof(struct pt_regs, r13), &sp)) {
|
|
orc_warn("missing regs for base reg R13 at ip %pB\n",
|
|
(void *)state->ip);
|
|
goto err;
|
|
}
|
|
break;
|
|
|
|
case ORC_REG_DI:
|
|
if (!get_reg(state, offsetof(struct pt_regs, di), &sp)) {
|
|
orc_warn("missing regs for base reg DI at ip %pB\n",
|
|
(void *)state->ip);
|
|
goto err;
|
|
}
|
|
break;
|
|
|
|
case ORC_REG_DX:
|
|
if (!get_reg(state, offsetof(struct pt_regs, dx), &sp)) {
|
|
orc_warn("missing regs for base reg DX at ip %pB\n",
|
|
(void *)state->ip);
|
|
goto err;
|
|
}
|
|
break;
|
|
|
|
default:
|
|
orc_warn("unknown SP base reg %d for ip %pB\n",
|
|
orc->sp_reg, (void *)state->ip);
|
|
goto err;
|
|
}
|
|
|
|
if (indirect) {
|
|
if (!deref_stack_reg(state, sp, &sp))
|
|
goto err;
|
|
}
|
|
|
|
/* Find IP, SP and possibly regs: */
|
|
switch (orc->type) {
|
|
case ORC_TYPE_CALL:
|
|
ip_p = sp - sizeof(long);
|
|
|
|
if (!deref_stack_reg(state, ip_p, &state->ip))
|
|
goto err;
|
|
|
|
state->ip = ftrace_graph_ret_addr(state->task, &state->graph_idx,
|
|
state->ip, (void *)ip_p);
|
|
|
|
state->sp = sp;
|
|
state->regs = NULL;
|
|
state->prev_regs = NULL;
|
|
state->signal = false;
|
|
break;
|
|
|
|
case ORC_TYPE_REGS:
|
|
if (!deref_stack_regs(state, sp, &state->ip, &state->sp)) {
|
|
orc_warn("can't dereference registers at %p for ip %pB\n",
|
|
(void *)sp, (void *)orig_ip);
|
|
goto err;
|
|
}
|
|
|
|
state->regs = (struct pt_regs *)sp;
|
|
state->prev_regs = NULL;
|
|
state->full_regs = true;
|
|
state->signal = true;
|
|
break;
|
|
|
|
case ORC_TYPE_REGS_IRET:
|
|
if (!deref_stack_iret_regs(state, sp, &state->ip, &state->sp)) {
|
|
orc_warn("can't dereference iret registers at %p for ip %pB\n",
|
|
(void *)sp, (void *)orig_ip);
|
|
goto err;
|
|
}
|
|
|
|
if (state->full_regs)
|
|
state->prev_regs = state->regs;
|
|
state->regs = (void *)sp - IRET_FRAME_OFFSET;
|
|
state->full_regs = false;
|
|
state->signal = true;
|
|
break;
|
|
|
|
default:
|
|
orc_warn("unknown .orc_unwind entry type %d for ip %pB\n",
|
|
orc->type, (void *)orig_ip);
|
|
goto err;
|
|
}
|
|
|
|
/* Find BP: */
|
|
switch (orc->bp_reg) {
|
|
case ORC_REG_UNDEFINED:
|
|
if (get_reg(state, offsetof(struct pt_regs, bp), &tmp))
|
|
state->bp = tmp;
|
|
break;
|
|
|
|
case ORC_REG_PREV_SP:
|
|
if (!deref_stack_reg(state, sp + orc->bp_offset, &state->bp))
|
|
goto err;
|
|
break;
|
|
|
|
case ORC_REG_BP:
|
|
if (!deref_stack_reg(state, state->bp + orc->bp_offset, &state->bp))
|
|
goto err;
|
|
break;
|
|
|
|
default:
|
|
orc_warn("unknown BP base reg %d for ip %pB\n",
|
|
orc->bp_reg, (void *)orig_ip);
|
|
goto err;
|
|
}
|
|
|
|
/* Prevent a recursive loop due to bad ORC data: */
|
|
if (state->stack_info.type == prev_type &&
|
|
on_stack(&state->stack_info, (void *)state->sp, sizeof(long)) &&
|
|
state->sp <= prev_sp) {
|
|
orc_warn("stack going in the wrong direction? ip=%pB\n",
|
|
(void *)orig_ip);
|
|
goto err;
|
|
}
|
|
|
|
preempt_enable();
|
|
return true;
|
|
|
|
err:
|
|
state->error = true;
|
|
|
|
the_end:
|
|
preempt_enable();
|
|
state->stack_info.type = STACK_TYPE_UNKNOWN;
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL_GPL(unwind_next_frame);
|
|
|
|
void __unwind_start(struct unwind_state *state, struct task_struct *task,
|
|
struct pt_regs *regs, unsigned long *first_frame)
|
|
{
|
|
memset(state, 0, sizeof(*state));
|
|
state->task = task;
|
|
|
|
if (!orc_init)
|
|
goto err;
|
|
|
|
/*
|
|
* Refuse to unwind the stack of a task while it's executing on another
|
|
* CPU. This check is racy, but that's ok: the unwinder has other
|
|
* checks to prevent it from going off the rails.
|
|
*/
|
|
if (task_on_another_cpu(task))
|
|
goto err;
|
|
|
|
if (regs) {
|
|
if (user_mode(regs))
|
|
goto the_end;
|
|
|
|
state->ip = regs->ip;
|
|
state->sp = regs->sp;
|
|
state->bp = regs->bp;
|
|
state->regs = regs;
|
|
state->full_regs = true;
|
|
state->signal = true;
|
|
|
|
} else if (task == current) {
|
|
asm volatile("lea (%%rip), %0\n\t"
|
|
"mov %%rsp, %1\n\t"
|
|
"mov %%rbp, %2\n\t"
|
|
: "=r" (state->ip), "=r" (state->sp),
|
|
"=r" (state->bp));
|
|
|
|
} else {
|
|
struct inactive_task_frame *frame = (void *)task->thread.sp;
|
|
|
|
state->sp = task->thread.sp + sizeof(*frame);
|
|
state->bp = READ_ONCE_NOCHECK(frame->bp);
|
|
state->ip = READ_ONCE_NOCHECK(frame->ret_addr);
|
|
state->signal = (void *)state->ip == ret_from_fork;
|
|
}
|
|
|
|
if (get_stack_info((unsigned long *)state->sp, state->task,
|
|
&state->stack_info, &state->stack_mask)) {
|
|
/*
|
|
* We weren't on a valid stack. It's possible that
|
|
* we overflowed a valid stack into a guard page.
|
|
* See if the next page up is valid so that we can
|
|
* generate some kind of backtrace if this happens.
|
|
*/
|
|
void *next_page = (void *)PAGE_ALIGN((unsigned long)state->sp);
|
|
state->error = true;
|
|
if (get_stack_info(next_page, state->task, &state->stack_info,
|
|
&state->stack_mask))
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* The caller can provide the address of the first frame directly
|
|
* (first_frame) or indirectly (regs->sp) to indicate which stack frame
|
|
* to start unwinding at. Skip ahead until we reach it.
|
|
*/
|
|
|
|
/* When starting from regs, skip the regs frame: */
|
|
if (regs) {
|
|
unwind_next_frame(state);
|
|
return;
|
|
}
|
|
|
|
/* Otherwise, skip ahead to the user-specified starting frame: */
|
|
while (!unwind_done(state) &&
|
|
(!on_stack(&state->stack_info, first_frame, sizeof(long)) ||
|
|
state->sp <= (unsigned long)first_frame))
|
|
unwind_next_frame(state);
|
|
|
|
return;
|
|
|
|
err:
|
|
state->error = true;
|
|
the_end:
|
|
state->stack_info.type = STACK_TYPE_UNKNOWN;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__unwind_start);
|