Michael Ellerman 6772faa1ba powerpc/perf: Fix deadlock caused by calling printk() in PMU exception ... In commit bc09c21 "Fix finding overflowed PMC in interrupt" we added a printk() to the PMU exception handler. Unfortunately that is not safe. The problem is that the PMU exception may run even when interrupts are soft disabled, aka NMI context. We do this so that we can profile parts of the kernel that have interrupts soft-disabled. But by calling printk() from the exception handler, we can potentially deadlock in the printk code on logbuf_lock, eg: [c00000038ba575c0] c000000000081928 .vprintk_emit+0xa8/0x540 [c00000038ba576a0] c0000000007bcde8 .printk+0x48/0x58 [c00000038ba57710] c000000000076504 .perf_event_interrupt+0x2d4/0x490 [c00000038ba57810] c00000000001f6f8 .performance_monitor_exception+0x48/0x60 [c00000038ba57880] c0000000000032cc performance_monitor_common+0x14c/0x180 --- Exception: f01 (Performance Monitor) at c0000000007b25d4 ._raw_spin_lock_irq +0x64/0xc0 [c00000038ba57bf0] c00000000007ed90 .devkmsg_read+0xd0/0x5a0 [c00000038ba57d00] c0000000001c2934 .vfs_read+0xc4/0x1e0 [c00000038ba57d90] c0000000001c2cd8 .SyS_read+0x58/0xd0 [c00000038ba57e30] c000000000009d54 syscall_exit+0x0/0x98 --- Exception: c01 (System Call) at 00001fffffbf6f7c SP (3ffff6d4de10) is in userspace Fix it by making sure we only call printk() when we are not in NMI context. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Cc: <stable@vger.kernel.org> # 3.9 Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>		2013-06-10 08:36:32 +10:00
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alpha
arc	ARC: lazy dcache flush broke gdb in non-aliasing configs	2013-05-25 14:15:55 +05:30
arm	arch, mm: Remove tlb_fast_mode()	2013-06-06 10:07:26 +09:00
arm64	arm64: don't kill the kernel on a bad esr from el0	2013-05-31 16:04:51 +01:00
avr32	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/egtvedt/linux-avr32	2013-05-22 18:06:57 -07:00
blackfin
c6x
cris
frv
h8300
hexagon
ia64	arch, mm: Remove tlb_fast_mode()	2013-06-06 10:07:26 +09:00
m32r
m68k	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k	2013-06-03 18:09:42 +09:00
metag
microblaze	microblaze: Use static inline functions in cacheflush.h	2013-06-03 11:33:23 +02:00
mips	mips/kvm: Use ENOIOCTLCMD to indicate unimplemented ioctls.	2013-06-03 10:58:55 +03:00
mn10300	MN10300: Need pci_iomap() and __pci_ioport_map() defining	2013-05-30 13:38:48 +09:00
openrisc
parisc	parisc: kernel: using strlcpy() instead of strcpy()	2013-06-01 14:29:01 +02:00
powerpc	powerpc/perf: Fix deadlock caused by calling printk() in PMU exception	2013-06-10 08:36:32 +10:00
s390	s390/pgtable: Fix gmap notifier address	2013-05-31 17:23:53 +02:00
score	score: remove redundant kcore_list entries	2013-05-25 10:27:27 -07:00
sh
sparc
tile
um
unicore32
x86	PCI update for v3.10:	2013-06-06 16:28:15 -07:00
xtensa
.gitignore
Kconfig	Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2013-05-15 14:04:00 -07:00