On 22.01.2025 03:31, Josh Poimboeuf wrote:
Objtool warns about calling pr_debug() from uaccess-enabled regions, and
rightfully so. Add a dbg_sec_uaccess() macro which temporarily disables
uaccess before doing the dynamic printk, and use that to add debug
messages throughout the uaccess-enabled regions.
Signed-off-by: Josh Poimboeuf <jpoim...@kernel.org>
diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c
@@ -53,12 +53,15 @@ static __always_inline int __read_fde(struct sframe_section
*sec,
sizeof(struct sframe_fde), Efault);
ip = sec->sframe_start + fde->start_addr;
- if (ip < sec->text_start || ip > sec->text_end)
+ if (ip < sec->text_start || ip > sec->text_end) {
+ dbg_sec_uaccess("bad fde num %d\n", fde_num);
return -EINVAL;
+ }
return 0;
Efault:
+ dbg_sec_uaccess("fde %d usercopy failed\n", fde_num);
return -EFAULT;
}
Add a similar debug message for SFRame FDE user copy failures?
diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c
@@ -125,6 +125,7 @@ static __always_inline int __find_fde(struct sframe_section
*sec,
return 0;
Efault:
+ dbg_sec_uaccess("fde usercopy failed\n");
return -EFAULT;
}
Printing the IP is probably not an option due to security concerns?
Printing the the CFA, FP, and RA offsets is too much traffic? To debug
issues on s390 I had to add tons of additional debug messages to make
sense of what was actually going on.
Regards,
Jens
--
Jens Remus
Linux on Z Development (D3303)
+49-7031-16-1128 Office
jre...@de.ibm.com
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