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tracing: Move duplicate code of trace_kprobe/eprobe.c into header
The functions: fetch_store_strlen_user() fetch_store_strlen() fetch_store_string_user() fetch_store_string() are identical in both trace_kprobe.c and trace_eprobe.c. Move them into a new header file trace_probe_kernel.h to share it. This code will later be used by the synthetic events as well. Marked for stable as a fix for a crash in synthetic events requires it. Link: https://lkml.kernel.org/r/20221012104534.467668078@goodmis.org Cc: stable@vger.kernel.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Tom Zanussi <zanussi@kernel.org> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Tom Zanussi <zanussi@kernel.org> Fixes: bd82631 ("tracing: Add support for dynamic strings to synthetic events") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Steven Rostedt (Google)
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,96 @@ | ||
| /* SPDX-License-Identifier: GPL-2.0 */ | ||
| #ifndef __TRACE_PROBE_KERNEL_H_ | ||
| #define __TRACE_PROBE_KERNEL_H_ | ||
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| /* | ||
| * This depends on trace_probe.h, but can not include it due to | ||
| * the way trace_probe_tmpl.h is used by trace_kprobe.c and trace_eprobe.c. | ||
| * Which means that any other user must include trace_probe.h before including | ||
| * this file. | ||
| */ | ||
| /* Return the length of string -- including null terminal byte */ | ||
| static nokprobe_inline int | ||
| kern_fetch_store_strlen_user(unsigned long addr) | ||
| { | ||
| const void __user *uaddr = (__force const void __user *)addr; | ||
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| return strnlen_user_nofault(uaddr, MAX_STRING_SIZE); | ||
| } | ||
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| /* Return the length of string -- including null terminal byte */ | ||
| static nokprobe_inline int | ||
| kern_fetch_store_strlen(unsigned long addr) | ||
| { | ||
| int ret, len = 0; | ||
| u8 c; | ||
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| #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE | ||
| if (addr < TASK_SIZE) | ||
| return kern_fetch_store_strlen_user(addr); | ||
| #endif | ||
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| do { | ||
| ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1); | ||
| len++; | ||
| } while (c && ret == 0 && len < MAX_STRING_SIZE); | ||
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| return (ret < 0) ? ret : len; | ||
| } | ||
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| /* | ||
| * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf | ||
| * with max length and relative data location. | ||
| */ | ||
| static nokprobe_inline int | ||
| kern_fetch_store_string_user(unsigned long addr, void *dest, void *base) | ||
| { | ||
| const void __user *uaddr = (__force const void __user *)addr; | ||
| int maxlen = get_loc_len(*(u32 *)dest); | ||
| void *__dest; | ||
| long ret; | ||
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| if (unlikely(!maxlen)) | ||
| return -ENOMEM; | ||
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| __dest = get_loc_data(dest, base); | ||
|
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| ret = strncpy_from_user_nofault(__dest, uaddr, maxlen); | ||
| if (ret >= 0) | ||
| *(u32 *)dest = make_data_loc(ret, __dest - base); | ||
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| return ret; | ||
| } | ||
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| /* | ||
| * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max | ||
| * length and relative data location. | ||
| */ | ||
| static nokprobe_inline int | ||
| kern_fetch_store_string(unsigned long addr, void *dest, void *base) | ||
| { | ||
| int maxlen = get_loc_len(*(u32 *)dest); | ||
| void *__dest; | ||
| long ret; | ||
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| #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE | ||
| if ((unsigned long)addr < TASK_SIZE) | ||
| return kern_fetch_store_string_user(addr, dest, base); | ||
| #endif | ||
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| if (unlikely(!maxlen)) | ||
| return -ENOMEM; | ||
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| __dest = get_loc_data(dest, base); | ||
|
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| /* | ||
| * Try to get string again, since the string can be changed while | ||
| * probing. | ||
| */ | ||
| ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen); | ||
| if (ret >= 0) | ||
| *(u32 *)dest = make_data_loc(ret, __dest - base); | ||
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| return ret; | ||
| } | ||
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| #endif /* __TRACE_PROBE_KERNEL_H_ */ |