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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
| commit | f4cdf7ca9a1fdcca413157df19753f388a5a224e (patch) | |
| tree | 60a31895b2446cd7fa27514e8c2843534a0de0da /lib/bug.c | |
| download | linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.zip | |
Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab:
- v4l2-core: added ISP statistics support and per-block validation
- v4l2-core: Allow unknown HDR10 white point and luminance
- New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor
- New codec: Milos: VPU v2.0 codec support
- isp driver: gained support for Dreamchip RPPX1 ISP framework
- vsp1 driver: gained support for RZ/T2H and RZ/N2H
- Novalake driver: gained CVS support for new NVL hardware
- dvb-core: fix feed leak on failed DMX_ADD_PID
- several driver fixes, cleanups and minor improvements
* tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits)
media: ipu-bridge: check all DMI entries when overriding sensor rotation
media: v4l2-async: avoid deleting unlinked ASC entry on link error
media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement
media: intel/ipu6: fix async notifier cleanup leak on parse error
media: staging/ipu7: fix async notifier UAF on probe error path
media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path
media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem()
media: rcar-isp: Fix VSPX reference leaks
media: rcar-isp: Release ISPCORE resources
media: i2c: imx415: Release runtime PM reference on VBLANK error
media: i2c: imx415: Return test pattern write errors
media: renesas: vsp1: Declare index variables in for loop statement
media: renesas: vsp1: Make reset control optional to support platforms without a reset line
media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs
media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs
media: nxp: imx8-isi: Add additional 32-bit RGB format support
media: nxp: imx8-isi: Add 16-bit raw Bayer format support
media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams
media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks
media: nxp: imx8-isi: Correct color map between V4L2 and ISI
...
Diffstat (limited to 'lib/bug.c')
| -rw-r--r-- | lib/bug.c | 313 |
1 files changed, 313 insertions, 0 deletions
diff --git a/lib/bug.c b/lib/bug.c new file mode 100644 index 000000000..7c1c2c27f --- /dev/null +++ b/lib/bug.c @@ -0,0 +1,313 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Generic support for BUG() + * + * This respects the following config options: + * + * CONFIG_BUG - emit BUG traps. Nothing happens without this. + * CONFIG_GENERIC_BUG - enable this code. + * CONFIG_GENERIC_BUG_RELATIVE_POINTERS - use 32-bit relative pointers for bug_addr and file + * CONFIG_DEBUG_BUGVERBOSE - emit full file+line information for each BUG + * + * CONFIG_BUG and CONFIG_DEBUG_BUGVERBOSE are potentially user-settable + * (though they're generally always on). + * + * CONFIG_GENERIC_BUG is set by each architecture using this code. + * + * To use this, your architecture must: + * + * 1. Set up the config options: + * - Enable CONFIG_GENERIC_BUG if CONFIG_BUG + * + * 2. Implement BUG (and optionally BUG_ON, WARN, WARN_ON) + * - Define HAVE_ARCH_BUG + * - Implement BUG() to generate a faulting instruction + * - NOTE: struct bug_entry does not have "file" or "line" entries + * when CONFIG_DEBUG_BUGVERBOSE is not enabled, so you must generate + * the values accordingly. + * + * 3. Implement the trap + * - In the illegal instruction trap handler (typically), verify + * that the fault was in kernel mode, and call report_bug() + * - report_bug() will return whether it was a false alarm, a warning, + * or an actual bug. + * - You must implement the is_valid_bugaddr(bugaddr) callback which + * returns true if the eip is a real kernel address, and it points + * to the expected BUG trap instruction. + * + * Jeremy Fitzhardinge <jeremy@goop.org> 2006 + */ + +#define pr_fmt(fmt) fmt + +#include <linux/list.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/bug.h> +#include <linux/sched.h> +#include <linux/rculist.h> +#include <linux/ftrace.h> +#include <linux/context_tracking.h> +#include <kunit/test-bug.h> + +extern struct bug_entry __start___bug_table[], __stop___bug_table[]; + +static inline unsigned long bug_addr(const struct bug_entry *bug) +{ +#ifdef CONFIG_GENERIC_BUG_RELATIVE_POINTERS + return (unsigned long)&bug->bug_addr_disp + bug->bug_addr_disp; +#else + return bug->bug_addr; +#endif +} + +#ifdef CONFIG_MODULES +/* Updates are protected by module mutex */ +static LIST_HEAD(module_bug_list); + +static struct bug_entry *module_find_bug(unsigned long bugaddr) +{ + struct bug_entry *bug; + struct module *mod; + + guard(rcu)(); + list_for_each_entry_rcu(mod, &module_bug_list, bug_list) { + unsigned int i; + + bug = mod->bug_table; + for (i = 0; i < mod->num_bugs; ++i, ++bug) + if (bugaddr == bug_addr(bug)) + return bug; + } + return NULL; +} + +void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, + struct module *mod) +{ + char *secstrings; + unsigned int i; + + mod->bug_table = NULL; + mod->num_bugs = 0; + + /* Find the __bug_table section, if present */ + secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; + for (i = 1; i < hdr->e_shnum; i++) { + if (strcmp(secstrings+sechdrs[i].sh_name, "__bug_table")) + continue; + mod->bug_table = (void *) sechdrs[i].sh_addr; + mod->num_bugs = sechdrs[i].sh_size / sizeof(struct bug_entry); + break; + } + + /* + * Strictly speaking this should have a spinlock to protect against + * traversals, but since we only traverse on BUG()s, a spinlock + * could potentially lead to deadlock and thus be counter-productive. + * Thus, this uses RCU to safely manipulate the bug list, since BUG + * must run in non-interruptive state. + */ + list_add_rcu(&mod->bug_list, &module_bug_list); +} + +void module_bug_cleanup(struct module *mod) +{ + list_del_rcu(&mod->bug_list); +} + +#else + +static inline struct bug_entry *module_find_bug(unsigned long bugaddr) +{ + return NULL; +} +#endif + +void bug_get_file_line(struct bug_entry *bug, const char **file, + unsigned int *line) +{ +#ifdef CONFIG_DEBUG_BUGVERBOSE +#ifdef CONFIG_GENERIC_BUG_RELATIVE_POINTERS + *file = (const char *)&bug->file_disp + bug->file_disp; +#else + *file = bug->file; +#endif + *line = bug->line; +#else + *file = NULL; + *line = 0; +#endif +} + +static const char *bug_get_format(struct bug_entry *bug) +{ + const char *format = NULL; +#ifdef HAVE_ARCH_BUG_FORMAT +#ifdef CONFIG_GENERIC_BUG_RELATIVE_POINTERS + /* + * Allow an architecture to: + * - relative encode NULL (difficult vs KASLR); + * - use a literal 0 (there are no valid objects inside + * the __bug_table itself to refer to after all); + * - use an empty string. + */ + if (bug->format_disp) + format = (const char *)&bug->format_disp + bug->format_disp; + if (format && format[0] == '\0') + format = NULL; +#else + format = bug->format; +#endif +#endif + return format; +} + +struct bug_entry *find_bug(unsigned long bugaddr) +{ + struct bug_entry *bug; + + for (bug = __start___bug_table; bug < __stop___bug_table; ++bug) + if (bugaddr == bug_addr(bug)) + return bug; + + return module_find_bug(bugaddr); +} + +static __printf(1, 0) +void __warn_printf(const char *fmt, struct pt_regs *regs) +{ + if (!fmt) + return; + +#ifdef HAVE_ARCH_BUG_FORMAT_ARGS + if (regs) { + struct arch_va_list _args; + va_list *args = __warn_args(&_args, regs); + + if (args) { + vprintk(fmt, *args); + return; + } + } +#endif + + pr_warn("%s", fmt); +} + +static enum bug_trap_type __report_bug(struct bug_entry *bug, unsigned long bugaddr, struct pt_regs *regs) +{ + bool warning, once, done, no_cut, has_args; + const char *file, *fmt; + unsigned int line; + + if (!bug) { + if (!is_valid_bugaddr(bugaddr)) + return BUG_TRAP_TYPE_NONE; + + bug = find_bug(bugaddr); + if (!bug) + return BUG_TRAP_TYPE_NONE; + } + + bug_get_file_line(bug, &file, &line); + fmt = bug_get_format(bug); + + warning = bug->flags & BUGFLAG_WARNING; + once = bug->flags & BUGFLAG_ONCE; + done = bug->flags & BUGFLAG_DONE; + no_cut = bug->flags & BUGFLAG_NO_CUT_HERE; + has_args = bug->flags & BUGFLAG_ARGS; + + /* + * Before the once logic so suppressed warnings do not consume + * the single-fire budget of WARN_ON_ONCE(). + */ + if (warning && kunit_is_suppressed_warning(true)) + return BUG_TRAP_TYPE_WARN; + + disable_trace_on_warning(); + + if (warning && once) { + if (done) + return BUG_TRAP_TYPE_WARN; + + /* + * Since this is the only store, concurrency is not an issue. + */ + bug->flags |= BUGFLAG_DONE; + } + + /* + * BUG() and WARN_ON() families don't print a custom debug message + * before triggering the exception handler, so we must add the + * "cut here" line now. WARN() issues its own "cut here" before the + * extra debugging message it writes before triggering the handler. + */ + if (!no_cut) { + pr_info(CUT_HERE); + __warn_printf(fmt, has_args ? regs : NULL); + } + + if (warning) { + /* this is a WARN_ON rather than BUG/BUG_ON */ + __warn(file, line, (void *)bugaddr, BUG_GET_TAINT(bug), regs, + NULL); + return BUG_TRAP_TYPE_WARN; + } + + if (file) + pr_crit("kernel BUG at %s:%u!\n", file, line); + else + pr_crit("kernel BUG at %pB [verbose debug info unavailable]\n", + (void *)bugaddr); + + return BUG_TRAP_TYPE_BUG; +} + +enum bug_trap_type report_bug_entry(struct bug_entry *bug, struct pt_regs *regs) +{ + enum bug_trap_type ret; + bool rcu; + + rcu = warn_rcu_enter(); + ret = __report_bug(bug, bug_addr(bug), regs); + warn_rcu_exit(rcu); + + return ret; +} + +enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs) +{ + enum bug_trap_type ret; + bool rcu; + + rcu = warn_rcu_enter(); + ret = __report_bug(NULL, bugaddr, regs); + warn_rcu_exit(rcu); + + return ret; +} + +static void clear_once_table(struct bug_entry *start, struct bug_entry *end) +{ + struct bug_entry *bug; + + for (bug = start; bug < end; bug++) + bug->flags &= ~BUGFLAG_DONE; +} + +void generic_bug_clear_once(void) +{ +#ifdef CONFIG_MODULES + struct module *mod; + + scoped_guard(rcu) { + list_for_each_entry_rcu(mod, &module_bug_list, bug_list) + clear_once_table(mod->bug_table, + mod->bug_table + mod->num_bugs); + } +#endif + + clear_once_table(__start___bug_table, __stop___bug_table); +} |
