forked from luck/tmp_suning_uos_patched
f91eb62f71
As I was testing a lot of my code recently, and having several "successes", I accidentally noticed in the dmesg this little line: start_kernel(): bug: interrupts were enabled *very* early, fixing it Sure enough, one of my patches two commits ago enabled interrupts early. The sad part here is that I never noticed it, and I ran several tests with ktest too, and ktest did not notice this line. What ktest looks for (and so does many other automated testing scripts) is a back trace produced by a WARN_ON() or BUG(). As a back trace was never produced, my buggy patch could have slipped into linux-next, or even worse, mainline. Adding a WARN(!irqs_disabled()) makes this bug a little more obvious: PID hash table entries: 4096 (order: 3, 32768 bytes) __ex_table already sorted, skipping sort Checking aperture... No AGP bridge found Calgary: detecting Calgary via BIOS EBDA area Calgary: Unable to locate Rio Grande table in EBDA - bailing! Memory: 2003252k/2054848k available (4857k kernel code, 460k absent, 51136k reserved, 6210k data, 1096k init) ------------[ cut here ]------------ WARNING: at /home/rostedt/work/git/linux-trace.git/init/main.c:543 start_kernel+0x21e/0x415() Hardware name: To Be Filled By O.E.M. Interrupts were enabled *very* early, fixing it Modules linked in: Pid: 0, comm: swapper/0 Not tainted 3.8.0-test+ #286 Call Trace: warn_slowpath_common+0x83/0x9b warn_slowpath_fmt+0x46/0x48 start_kernel+0x21e/0x415 x86_64_start_reservations+0x10e/0x112 x86_64_start_kernel+0x102/0x111 ---[ end trace 007d8b0491b4f5d8 ]--- Preemptible hierarchical RCU implementation. RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=4. NR_IRQS:4352 nr_irqs:712 16 Console: colour VGA+ 80x25 console [ttyS0] enabled, bootconsole disabled Do you see it? The original version of this patch just slapped a WARN_ON() in there and kept the printk(). Ard van Breemen suggested using the WARN() interface, which makes the code a bit cleaner. Also, while examining other warnings in init/main.c, I found two other locations that deserve a bloody murder scream if their conditions are hit, and updated them accordingly. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Cc: Ard van Breemen <ard@telegraafnet.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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| .. | ||
| calibrate.c | ||
| do_mounts_initrd.c | ||
| do_mounts_md.c | ||
| do_mounts_rd.c | ||
| do_mounts.c | ||
| do_mounts.h | ||
| init_task.c | ||
| initramfs.c | ||
| Kconfig | ||
| main.c | ||
| Makefile | ||
| noinitramfs.c | ||
| version.c | ||