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It was reported that trace_printk() was not reporting properly
values that came after a dereference pointer. trace_printk() utilizes vbin_printf() and bstr_printf() to keep the overhead of tracing down. vbin_printf() does not do any conversions and just stors the string format and the raw arguments into the buffer. bstr_printf() is used to read the buffer and does the conversions to complete the printf() output. This can be troublesome with dereferenced pointers because the reference may be different from the time vbin_printf() is called to the time bstr_printf() is called. To fix this, a prior commit changed vbin_printf() to convert dereferenced pointers into strings and load the converted string into the buffer. But the change to bstr_printf() had an off-by-one error and didn't account for the nul character at the end of the string and this corrupted the rest of the values in the format that came after a dereferenced pointer. -----BEGIN PGP SIGNATURE----- iIoEABYIADIWIQRRSw7ePDh/lE+zeZMp5XQQmuv6qgUCW737iRQccm9zdGVkdEBn b29kbWlzLm9yZwAKCRAp5XQQmuv6qnraAQDVbp0aWOpS73YUVbW/bArC8t8Z6/9h bXLeCdSSa1BHswD+K+kj7NiVrxIzyXrotb40JoscLsaXSIEJjlNFHQKqxQQ= =4BpJ -----END PGP SIGNATURE----- Merge tag 'trace-v4.19-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Steven writes: "vsprint fix: It was reported that trace_printk() was not reporting properly values that came after a dereference pointer. trace_printk() utilizes vbin_printf() and bstr_printf() to keep the overhead of tracing down. vbin_printf() does not do any conversions and just stors the string format and the raw arguments into the buffer. bstr_printf() is used to read the buffer and does the conversions to complete the printf() output. This can be troublesome with dereferenced pointers because the reference may be different from the time vbin_printf() is called to the time bstr_printf() is called. To fix this, a prior commit changed vbin_printf() to convert dereferenced pointers into strings and load the converted string into the buffer. But the change to bstr_printf() had an off-by-one error and didn't account for the nul character at the end of the string and this corrupted the rest of the values in the format that came after a dereferenced pointer." * tag 'trace-v4.19-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: vsprintf: Fix off-by-one bug in bstr_printf() processing dereferenced pointers
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commit
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1 changed files with 1 additions and 1 deletions
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@ -2794,7 +2794,7 @@ int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
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copy = end - str;
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memcpy(str, args, copy);
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str += len;
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args += len;
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args += len + 1;
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}
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}
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if (process)
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