On Fri, Sep 14, 2018 at 12:35:44PM +0000, Christophe Leroy wrote: > On a powerpc 8xx, 'btc' fails as follows: > > Entering kdb (current=0x(ptrval), pid 282) due to Keyboard Entry > kdb> btc > btc: cpu status: Currently on cpu 0 > Available cpus: 0 > kdb_getarea: Bad address 0x0 > > when booting the kernel with 'debug_boot_weak_hash', it fails as well > > Entering kdb (current=0xba99ad80, pid 284) due to Keyboard Entry > kdb> btc > btc: cpu status: Currently on cpu 0 > Available cpus: 0 > kdb_getarea: Bad address 0xba99ad80 > > On other platforms, Oopses have been observed too, see > https://github.com/linuxppc/linux/issues/139 > > This is due to btc calling 'btt' with %p pointer as an argument. > > This patch replaces %p by %px to get the real pointer value as > expected by 'btt' > > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> # 4.15+ Would a Fixes: be better here? Fixes: ad67b74d2469d9b82 ("printk: hash addresses printed with %p") No blame attached to Tobin, but the fixes makes it super clear what changed and why this breaks kdb (which was not explicitly called out the patch description). Daniel. > --- > kernel/debug/kdb/kdb_bt.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c > index 6ad4a9fcbd6f..7921ae4fca8d 100644 > --- a/kernel/debug/kdb/kdb_bt.c > +++ b/kernel/debug/kdb/kdb_bt.c > @@ -179,14 +179,14 @@ kdb_bt(int argc, const char **argv) > kdb_printf("no process for cpu %ld\n", cpu); > return 0; > } > - sprintf(buf, "btt 0x%p\n", KDB_TSK(cpu)); > + sprintf(buf, "btt 0x%px\n", KDB_TSK(cpu)); > kdb_parse(buf); > return 0; > } > kdb_printf("btc: cpu status: "); > kdb_parse("cpu\n"); > for_each_online_cpu(cpu) { > - sprintf(buf, "btt 0x%p\n", KDB_TSK(cpu)); > + sprintf(buf, "btt 0x%px\n", KDB_TSK(cpu)); > kdb_parse(buf); > touch_nmi_watchdog(); > } > -- > 2.13.3 >
