lwn.git/arch/x86/kernel/dumpstack_64.c, branch v4.3.2

x86/kernel: Use kstack_end() in dumpstack_64.c

2015-02-23T17:37:13+00:00

i386 is already using kstack_end() in dumpstack_32.c. We should also use it to make the code clearer and unify the stack printing logic some more. Suggested-by: Ingo Molnar Signed-off-by: Adrien Schildknecht Acked-by: Steven Rostedt Cc: c: Linus Torvalds Link: http://lkml.kernel.org/r/1424618638-6375-1-git-send-email-adrien+dev@schischi.me Signed-off-by: Borislav Petkov

x86/kernel: Fix output of show_stack_log_lvl()

2015-02-23T17:34:42+00:00

show_stack_log_lvl() does not set the log level after a new line, the following messages printed with pr_cont() are thus assigned to the default log level. This patch prepends the log level to the next message following a new line. print_trace_address() uses printk(log_lvl). Using printk() with just a log level is ignored and thus has no effect on the next pr_cont(). We need to prepend the log level directly into the message. Signed-off-by: Adrien Schildknecht Acked-by: Ingo Molnar Cc: Steven Rostedt Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1424399661-20327-1-git-send-email-adrien+dev@schischi.me Signed-off-by: Borislav Petkov

x86_64, traps: Stop using IST for #SS

2014-11-23T21:56:19+00:00

On a 32-bit kernel, this has no effect, since there are no IST stacks. On a 64-bit kernel, #SS can only happen in user code, on a failed iret to user space, a canonical violation on access via RSP or RBP, or a genuine stack segment violation in 32-bit kernel code. The first two cases don't need IST, and the latter two cases are unlikely fatal bugs, and promoting them to double faults would be fine. This fixes a bug in which the espfix64 code mishandles a stack segment violation. This saves 4k of memory per CPU and a tiny bit of code. Signed-off-by: Andy Lutomirski Reviewed-by: Thomas Gleixner Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds

x86: Fix dumpstack_64 irq stack handling

2014-04-02T18:46:50+00:00

Commit 2223f6f6eeaa "x86: Clean up dumpstack_64.c code" changed the irq_stack processing a little from what it was before. The irq_stack_end variable needed to be cleared after its first use. By setting irq_stack to the per cpu irq_stack and passing that to analyze_stack(), and then clearing it after it is processed, we can get back the original behavior. Signed-off-by: Steven Rostedt Signed-off-by: Linus Torvalds

x86: Fix dumpstack_64 to keep state of "used" variable in loop

2014-04-02T18:46:50+00:00

Commit 2223f6f6eeaa "x86: Clean up dumpstack_64.c code" moved the used variable to a local within the loop, but the in_exception_stack() depended on being non-volatile with the ability to change it. By always re-initializing the "used" variable to zero, it would cause the in_exception_stack() to return the same thing each time, and cause the dump_stack loop to go into an infinite loop. Reported-by: Linus Torvalds Signed-off-by: Steven Rostedt Signed-off-by: Linus Torvalds

x86: Clean up dumpstack_64.c code

2014-03-07T00:56:55+00:00

The dump_trace() function in dumpstack_64.c is hard to follow. The test for exception stack is processed differently than the test for irq stack, and the normal stack is outside completely. By restructuring this code to have all the stacks determined by a single function that returns an enum of the following: STACK_IS_NORMAL STACK_IS_EXCEPTION STACK_IS_IRQ STACK_IS_UNKNOWN and has the logic of each within a switch statement. This should make the code much easier to read and understand. Link: http://lkml.kernel.org/r/20110806012354.684598995@goodmis.org Cc: Andrew Morton Cc: Peter Zijlstra Cc: Brian Gerst Signed-off-by: Steven Rostedt Link: http://lkml.kernel.org/r/20140206144322.086050042@goodmis.org Signed-off-by: H. Peter Anvin

dump_stack: unify debug information printed by show_regs()

2013-05-01T00:04:02+00:00

show_regs() is inherently arch-dependent but it does make sense to print generic debug information and some archs already do albeit in slightly different forms. This patch introduces a generic function to print debug information from show_regs() so that different archs print out the same information and it's much easier to modify what's printed. show_regs_print_info() prints out the same debug info as dump_stack() does plus task and thread_info pointers. * Archs which didn't print debug info now do. alpha, arc, blackfin, c6x, cris, frv, h8300, hexagon, ia64, m32r, metag, microblaze, mn10300, openrisc, parisc, score, sh64, sparc, um, xtensa * Already prints debug info. Replaced with show_regs_print_info(). The printed information is superset of what used to be there. arm, arm64, avr32, mips, powerpc, sh32, tile, unicore32, x86 * s390 is special in that it used to print arch-specific information along with generic debug info. Heiko and Martin think that the arch-specific extra isn't worth keeping s390 specfic implementation. Converted to use the generic version. Note that now all archs print the debug info before actual register dumps. An example BUG() dump follows. kernel BUG at /work/os/work/kernel/workqueue.c:4841! invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #7 Hardware name: empty empty/S3992, BIOS 080011 10/26/2007 task: ffff88007c85e040 ti: ffff88007c860000 task.ti: ffff88007c860000 RIP: 0010:[] [] init_workqueues+0x4/0x6 RSP: 0000:ffff88007c861ec8 EFLAGS: 00010246 RAX: ffff88007c861fd8 RBX: ffffffff824466a8 RCX: 0000000000000001 RDX: 0000000000000046 RSI: 0000000000000001 RDI: ffffffff8234a07a RBP: ffff88007c861ec8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8234a07a R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88007dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: ffff88015f7ff000 CR3: 00000000021f1000 CR4: 00000000000007f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Stack: ffff88007c861ef8 ffffffff81000312 ffffffff824466a8 ffff88007c85e650 0000000000000003 0000000000000000 ffff88007c861f38 ffffffff82335e5d ffff88007c862080 ffffffff8223d8c0 ffff88007c862080 ffffffff81c47760 Call Trace: [] do_one_initcall+0x122/0x170 [] kernel_init_freeable+0x9b/0x1c8 [] ? rest_init+0x140/0x140 [] kernel_init+0xe/0xf0 [] ret_from_fork+0x7c/0xb0 [] ? rest_init+0x140/0x140 ... v2: Typo fix in x86-32. v3: CPU number dropped from show_regs_print_info() as dump_stack_print_info() has been updated to print it. s390 specific implementation dropped as requested by s390 maintainers. Signed-off-by: Tejun Heo Acked-by: David S. Miller Acked-by: Jesper Nilsson Cc: Heiko Carstens Cc: Martin Schwidefsky Cc: Bjorn Helgaas Cc: Fengguang Wu Cc: Mike Frysinger Cc: Vineet Gupta Cc: Sam Ravnborg Acked-by: Chris Metcalf [tile bits] Acked-by: Richard Kuo [hexagon bits] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

x86: Move call to print_modules() out of show_regs()

2012-06-20T12:33:48+00:00

Printing the list of loaded modules is really unrelated to what this function is about, and is particularly unnecessary in the context of the SysRQ key handling (gets printed so far over and over). It should really be the caller of the function to decide whether this piece of information is useful (and to avoid redundantly printing it). Signed-off-by: Jan Beulich Link: http://lkml.kernel.org/r/4FDF21A4020000780008A67F@nat28.tlf.novell.com Signed-off-by: Ingo Molnar

x86/debug: Add KERN_ to bare printks, convert printks to pr_

2012-06-06T07:17:22+00:00

Use a more current logging style: - Bare printks should have a KERN_ for consistency's sake - Add pr_fmt where appropriate - Neaten some macro definitions - Convert some Ok output to OK - Use "%s: ", __func__ in pr_fmt for summit - Convert some printks to pr_ Message output is not identical in all cases. Signed-off-by: Joe Perches Cc: levinsasha928@gmail.com Link: http://lkml.kernel.org/r/1337655007.24226.10.camel@joe2Laptop [ merged two similar patches, tidied up the changelog ] Signed-off-by: Ingo Molnar

x86: Avoid double stack traces with show_regs()

2012-05-09T09:44:42+00:00

What was called show_registers() so far already showed a stack trace for kernel faults, and kernel_stack_pointer() isn't even valid to be used for faults from user mode, hence it was pointless for show_regs() to call show_trace() after show_registers(). Simply rename show_registers() to show_regs() and eliminate the old definition. Signed-off-by: Jan Beulich Cc: Linus Torvalds Cc: Andrew Morton Cc: Arjan van de Ven Cc: Frederic Weisbecker Link: http://lkml.kernel.org/r/4FAA3D3902000078000826E1@nat28.tlf.novell.com Signed-off-by: Ingo Molnar