From d2beeb3bc74ec897ced7309c3a104fa4b3be0ac3 Mon Sep 17 00:00:00 2001 From: Peter Oberparleiter Date: Wed, 9 Jun 2021 14:05:56 +0200 Subject: [PATCH] s390/debug: Remove pointer obfuscation When read via debugfs, s390dbf debug-views print the kernel address of the call-site that created a trace entry. The kernel's %p pointer hashing feature obfuscates this address, and commit 860ec7c6e21c ("s390/debug: use pK for kernel pointers") made this obfuscation configurable via the kptr_restrict sysctl. Obfuscation of kernel address data printed via s390dbf debug-views does not add any additional protection since the associated debugfs files are only accessible to the root user that typically has enough other means to obtain kernel address data. Also trace payload data may contain binary representations of kernel addresses as part of logged data structues. Requiring such payload data to be obfuscated as well would be impractical and greatly diminish the use of s390dbf. Therefore completely remove pointer obfuscation from s390dbf debug-views. Reviewed-by: Steffen Maier Acked-by: Heiko Carstens Signed-off-by: Peter Oberparleiter Signed-off-by: Vasily Gorbik --- arch/s390/kernel/debug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c index bb958d32bd81..09b6c6402f9b 100644 --- a/arch/s390/kernel/debug.c +++ b/arch/s390/kernel/debug.c @@ -1418,7 +1418,7 @@ int debug_dflt_header_fn(debug_info_t *id, struct debug_view *view, else except_str = "-"; caller = (unsigned long) entry->caller; - rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %04u %pK ", + rc += sprintf(out_buf, "%02i %011ld:%06lu %1u %1s %04u %px ", area, sec, usec, level, except_str, entry->cpu, (void *)caller); return rc; -- 2.20.1