#ifndef _ASM_GENERIC_BUG_H #define _ASM_GENERIC_BUG_H #include #ifdef CONFIG_GENERIC_BUG #define BUGFLAG_WARNING (1 << 0) #define BUGFLAG_TAINT(taint) (BUGFLAG_WARNING | ((taint) << 8)) #define BUG_GET_TAINT(bug) ((bug)->flags >> 8) #endif #ifndef __ASSEMBLY__ #include #ifdef CONFIG_BUG #ifdef CONFIG_GENERIC_BUG struct bug_entry { #ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS unsigned long bug_addr; #else signed int bug_addr_disp; #endif #ifdef CONFIG_DEBUG_BUGVERBOSE #ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS const char *file; #else signed int file_disp; #endif unsigned short line; #endif unsigned short flags; }; #endif /* CONFIG_GENERIC_BUG */ /* * Don't use BUG() or BUG_ON() unless there's really no way out; one * example might be detecting data structure corruption in the middle * of an operation that can't be backed out of. If the (sub)system * can somehow continue operating, perhaps with reduced functionality, * it's probably not BUG-worthy. * * If you're tempted to BUG(), think again: is completely giving up * really the *only* solution? There are usually better options, where * users don't need to reboot ASAP and can mostly shut down cleanly. */ #ifndef HAVE_ARCH_BUG #define BUG() do { \ printk("BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \ panic("BUG!"); \ } while (0) #endif #ifndef HAVE_ARCH_BUG_ON #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) #endif /* * WARN(), WARN_ON(), WARN_ON_ONCE, and so on can be used to report * significant issues that need prompt attention if they should ever * appear at runtime. Use the versions with printk format strings * to provide better diagnostics. */ #ifndef __WARN_TAINT extern __printf(3, 4) void warn_slowpath_fmt(const char *file, const int line, const char *fmt, ...); extern __printf(4, 5) void warn_slowpath_fmt_taint(const char *file, const int line, unsigned taint, const char *fmt, ...); extern void warn_slowpath_null(const char *file, const int line); #define WANT_WARN_ON_SLOWPATH #define __WARN() warn_slowpath_null(__FILE__, __LINE__) #define __WARN_printf(arg...) warn_slowpath_fmt(__FILE__, __LINE__, arg) #define __WARN_printf_taint(taint, arg...) \ warn_slowpath_fmt_taint(__FILE__, __LINE__, taint, arg) #else #define __WARN() __WARN_TAINT(TAINT_WARN) #define __WARN_printf(arg...) do { printk(arg); __WARN(); } while (0) #define __WARN_printf_taint(taint, arg...) \ do { printk(arg); __WARN_TAINT(taint); } while (0) #endif /* used internally by panic.c */ struct warn_args; void __warn(const char *file, int line, void *caller, unsigned taint, struct pt_regs *regs, struct warn_args *args); #ifndef WARN_ON #define WARN_ON(condition) ({ \ int __ret_warn_on = !!(condition); \ if (unlikely(__ret_warn_on)) \ __WARN(); \ unlikely(__ret_warn_on); \ }) #endif #ifndef WARN #define WARN(condition, format...) ({ \ int __ret_warn_on = !!(condition); \ if (unlikely(__ret_warn_on)) \ __WARN_printf(format); \ unlikely(__ret_warn_on); \ }) #endif #define WARN_TAINT(condition, taint, format...) ({ \ int __ret_warn_on = !!(condition); \ if (unlikely(__ret_warn_on)) \ __WARN_printf_taint(taint, format); \ unlikely(__ret_warn_on); \ }) #define WARN_ON_ONCE(condition) ({ \ static bool __section(.data.unlikely) __warned; \ int __ret_warn_once = !!(condition); \ \ if (unlikely(__ret_warn_once && !__warned)) { \ __warned = true; \ WARN_ON(1); \ } \ unlikely(__ret_warn_once); \ }) #define WARN_ONCE(condition, format...) ({ \ static bool __section(.data.unlikely) __warned; \ int __ret_warn_once = !!(condition); \ \ if (unlikely(__ret_warn_once && !__warned)) { \ __warned = true; \ WARN(1, format); \ } \ unlikely(__ret_warn_once); \ }) #define WARN_TAINT_ONCE(condition, taint, format...) ({ \ static bool __section(.data.unlikely) __warned; \ int __ret_warn_once = !!(condition); \ \ if (unlikely(__ret_warn_once && !__warned)) { \ __warned = true; \ WARN_TAINT(1, taint, format); \ } \ unlikely(__ret_warn_once); \ }) #else /* !CONFIG_BUG */ #ifndef HAVE_ARCH_BUG #define BUG() do {} while (1) #endif #ifndef HAVE_ARCH_BUG_ON #define BUG_ON(condition) do { if (condition) BUG(); } while (0) #endif #ifndef HAVE_ARCH_WARN_ON #define WARN_ON(condition) ({ \ int __ret_warn_on = !!(condition); \ unlikely(__ret_warn_on); \ }) #endif #ifndef WARN #define WARN(condition, format...) ({ \ int __ret_warn_on = !!(condition); \ no_printk(format); \ unlikely(__ret_warn_on); \ }) #endif #define WARN_ON_ONCE(condition) WARN_ON(condition) #define WARN_ONCE(condition, format...) WARN(condition, format) #define WARN_TAINT(condition, taint, format...) WARN(condition, format) #define WARN_TAINT_ONCE(condition, taint, format...) WARN(condition, format) #endif /* * WARN_ON_SMP() is for cases that the warning is either * meaningless for !SMP or may even cause failures. * This is usually used for cases that we have * WARN_ON(!spin_is_locked(&lock)) checks, as spin_is_locked() * returns 0 for uniprocessor settings. * It can also be used with values that are only defined * on SMP: * * struct foo { * [...] * #ifdef CONFIG_SMP * int bar; * #endif * }; * * void func(struct foo *zoot) * { * WARN_ON_SMP(!zoot->bar); * * For CONFIG_SMP, WARN_ON_SMP() should act the same as WARN_ON(), * and should be a nop and return false for uniprocessor. * * if (WARN_ON_SMP(x)) returns true only when CONFIG_SMP is set * and x is true. */ #ifdef CONFIG_SMP # define WARN_ON_SMP(x) WARN_ON(x) #else /* * Use of ({0;}) because WARN_ON_SMP(x) may be used either as * a stand alone line statement or as a condition in an if () * statement. * A simple "0" would cause gcc to give a "statement has no effect" * warning. */ # define WARN_ON_SMP(x) ({0;}) #endif #endif /* __ASSEMBLY__ */ #endif value") fw_load_abort() could be called twice and lead us to a kernel crash. This happens only when the firmware fallback mechanism (regular or custom) is used. The fallback mechanism exposes a sysfs interface for userspace to upload a file and notify the kernel when the file is loaded and ready, or to cancel an upload by echo'ing -1 into on the loading file: echo -n "-1" > /sys/$DEVPATH/loading This will call fw_load_abort(). Some distributions actually have a udev rule in place to *always* immediately cancel all firmware fallback mechanism requests (Debian), they have: $ cat /lib/udev/rules.d/50-firmware.rules # stub for immediately telling the kernel that userspace firmware loading # failed; necessary to avoid long timeouts with CONFIG_FW_LOADER_USER_HELPER=y SUBSYSTEM=="firmware", ACTION=="add", ATTR{loading}="-1 Distributions with this udev rule would run into this crash only if the fallback mechanism is used. Since most distributions disable by default using the fallback mechanism (CONFIG_FW_LOADER_USER_HELPER_FALLBACK), this would typicaly mean only 2 drivers which *require* the fallback mechanism could typically incur a crash: drivers/firmware/dell_rbu.c and the drivers/leds/leds-lp55xx-common.c driver. Distributions enabling CONFIG_FW_LOADER_USER_HELPER_FALLBACK by default are obviously more exposed to this crash. The crash happens because after commit 5b029624948d ("firmware: do not use fw_lock for fw_state protection") and subsequent fix commit 5d47ec02c37ea6 ("firmware: Correct handling of fw_state_wait() return value") a race can happen between this cancelation and the firmware fw_state_wait_timeout() being woken up after a state change with which fw_load_abort() as that calls swake_up(). Upon error fw_state_wait_timeout() will also again call fw_load_abort() and trigger a null reference. At first glance we could just fix this with a !buf check on fw_load_abort() before accessing buf->fw_st, however there is a logical issue in having a state machine used for the fallback mechanism and preventing access from it once we abort as its inside the buf (buf->fw_st). The firmware_class.c code is setting the buf to NULL to annotate an abort has occurred. Replace this mechanism by simply using the state check instead. All the other code in place already uses similar checks for aborting as well so no further changes are needed. An oops can be reproduced with the new fw_fallback.sh fallback mechanism cancellation test. Either cancelling the fallback mechanism or the custom fallback mechanism triggers a crash. mcgrof@piggy ~/linux-next/tools/testing/selftests/firmware (git::20170111-fw-fixes)$ sudo ./fw_fallback.sh ./fw_fallback.sh: timeout works ./fw_fallback.sh: firmware comparison works ./fw_fallback.sh: fallback mechanism works [ this then sits here when it is trying the cancellation test ] Kernel log: test_firmware: loading 'nope-test-firmware.bin' misc test_firmware: Direct firmware load for nope-test-firmware.bin failed with error -2 misc test_firmware: Falling back to user helper BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 IP: _request_firmware+0xa27/0xad0 PGD 0 Oops: 0000 [#1] SMP Modules linked in: test_firmware(E) ... etc ... CPU: 1 PID: 1396 Comm: fw_fallback.sh Tainted: G W E 4.10.0-rc3-next-20170111+ #30 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.1-0-g8891697-prebuilt.qemu-project.org 04/01/2014 task: ffff9740b27f4340 task.stack: ffffbb15c0bc8000 RIP: 0010:_request_firmware+0xa27/0xad0 RSP: 0018:ffffbb15c0bcbd10 EFLAGS: 00010246 RAX: 00000000fffffffe RBX: ffff9740afe5aa80 RCX: 0000000000000000 RDX: ffff9740b27f4340 RSI: 0000000000000283 RDI: 0000000000000000 RBP: ffffbb15c0bcbd90 R08: ffffbb15c0bcbcd8 R09: 0000000000000000 R10: 0000000894a0d4b1 R11: 000000000000008c R12: ffffffffc0312480 R13: 0000000000000005 R14: ffff9740b1c32400 R15: 00000000000003e8 FS: 00007f8604422700(0000) GS:ffff9740bfc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000038 CR3: 000000012164c000 CR4: 00000000000006e0 Call Trace: request_firmware+0x37/0x50 trigger_request_store+0x79/0xd0 [test_firmware] dev_attr_store+0x18/0x30 sysfs_kf_write+0x37/0x40 kernfs_fop_write+0x110/0x1a0 __vfs_write+0x37/0x160 ? _cond_resched+0x1a/0x50 vfs_write+0xb5/0x1a0 SyS_write+0x55/0xc0 ? trace_do_page_fault+0x37/0xd0 entry_SYSCALL_64_fastpath+0x1e/0xad RIP: 0033:0x7f8603f49620 RSP: 002b:00007fff6287b788 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000055c307b110a0 RCX: 00007f8603f49620 RDX: 0000000000000016 RSI: 000055c3084d8a90 RDI: 0000000000000001 RBP: 0000000000000016 R08: 000000000000c0ff R09: 000055c3084d6336 R10: 000055c307b108b0 R11: 0000000000000246 R12: 000055c307b13c80 R13: 000055c3084d6320 R14: 0000000000000000 R15: 00007fff6287b950 Code: 9f 64 84 e8 9c 61 fe ff b8 f4 ff ff ff e9 6b f9 ff ff 48 c7 c7 40 6b 8d 84 89 45 a8 e8 43 84 18 00 49 8b be 00 03 00 00 8b 45 a8 <83> 7f 38 02 74 08 e8 6e ec ff ff 8b 45 a8 49 c7 86 00 03 00 00 RIP: _request_firmware+0xa27/0xad0 RSP: ffffbb15c0bcbd10 CR2: 0000000000000038 ---[ end trace 6d94ac339c133e6f ]--- Fixes: 5d47ec02c37e ("firmware: Correct handling of fw_state_wait() return value") Reported-and-Tested-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reported-and-Tested-by: Patrick Bruenn <p.bruenn@beckhoff.com> Reported-by: Chris Wilson <chris@chris-wilson.co.uk> CC: <stable@vger.kernel.org> [3.10+] Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/net/atmclip.h')