On Wed, Jul 21, 2021 at 10:04:13AM -0400, Steven Rostedt wrote:

On Tue, 20 Jul 2021 23:48:47 +0200
Pavel Machek [off-list ref] wrote:

quoted

Hi!

quoted

[ Upstream commit a948b1142cae66785521a389cab2cce74069b547 ]

Since commit 9a6944fee68e ("tracing: Add a verifier to check string
pointers for trace events"), which was merged in v5.13-rc1,
TP_printk() no longer tacitly supports the "%.*s" format specifier.

These are low value tracepoints, so just remove them.

So I understand we want this for mainline, but AFAICT 5.10 does not
have 9a6944fee68e ("tracing: Add a verifier to check string pointers
for trace events") commit, so this does not fix any bug and removal of
tracepoints can be surprising.

Thanks for pointing this out. I get so many stable patches, I don't
have time to look at all of them.

Greg, I don't think this should be backported. The verifier code had a
bug in it that broke the '%.*s' formats. This patch removed the good
code because of the broken code.

See eb01f5353bdaa ("tracing: Handle %.*s in trace_check_vprintf()")

Uh, yes, I'll drop it. Thanks for catching this!

-- 
Thanks,
Sasha