binfmt_elf, coredump: Log the reason of the failed core dumps

index a43897b03ce9..cfe84b9436af 100644
@@ -1994,8 +1994,11 @@ static int elf_core_dump(struct coredump_params *cprm)
 	 * Collect all the non-memory information about the process for the
 	 * notes.  This also sets up the file header.
 	 */
-	if (!fill_note_info(&elf, e_phnum, &info, cprm))
+	if (!fill_note_info(&elf, e_phnum, &info, cprm)) {
+		pr_err_ratelimited("Error collecting note info, core dump of %s(PID %d) failed\n",
+			current->comm, current->pid);
 		goto end_coredump;
+	}
 
 	has_dumped = 1;
 

@@ -2010,8 +2013,11 @@ static int elf_core_dump(struct coredump_params *cprm)
 		sz += elf_coredump_extra_notes_size();
 
 		phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
-		if (!phdr4note)
+		if (!phdr4note) {
+			pr_err_ratelimited("Error allocating program headers note entry, core dump of %s(PID %d) failed\n",
+				current->comm, current->pid);
 			goto end_coredump;
+		}
 
 		fill_elf_note_phdr(phdr4note, sz, offset);
 		offset += sz;

@@ -2025,18 +2031,27 @@ static int elf_core_dump(struct coredump_params *cprm)
 
 	if (e_phnum == PN_XNUM) {
 		shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
-		if (!shdr4extnum)
+		if (!shdr4extnum) {
+			pr_err_ratelimited("Error allocating extra program headers, core dump of %s(PID %d) failed\n",
+				current->comm, current->pid);
 			goto end_coredump;
+		}
 		fill_extnum_info(&elf, shdr4extnum, e_shoff, segs);
 	}
 
 	offset = dataoff;
 
-	if (!dump_emit(cprm, &elf, sizeof(elf)))
+	if (!dump_emit(cprm, &elf, sizeof(elf))) {
+		pr_err_ratelimited("Error emitting the ELF header, core dump of %s(PID %d) failed\n",
+			current->comm, current->pid);
 		goto end_coredump;
+	}
 
-	if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
+	if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note))) {
+		pr_err_ratelimited("Error emitting the program header for notes, core dump of %s(PID %d) failed\n",
+			current->comm, current->pid);
 		goto end_coredump;
+	}
 
 	/* Write program headers for segments dump */
 	for (i = 0; i < cprm->vma_count; i++) {

@@ -2059,20 +2074,32 @@ static int elf_core_dump(struct coredump_params *cprm)
 			phdr.p_flags |= PF_X;
 		phdr.p_align = ELF_EXEC_PAGESIZE;
 
-		if (!dump_emit(cprm, &phdr, sizeof(phdr)))
+		if (!dump_emit(cprm, &phdr, sizeof(phdr))) {
+			pr_err_ratelimited("Error emitting program headers, core dump of %s(PID %d) failed\n",
+				current->comm, current->pid);
 			goto end_coredump;
+		}
 	}
 
-	if (!elf_core_write_extra_phdrs(cprm, offset))
+	if (!elf_core_write_extra_phdrs(cprm, offset)) {
+		pr_err_ratelimited("Error writing out extra program headers, core dump of %s(PID %d) failed\n",
+			current->comm, current->pid);
 		goto end_coredump;
+	}
 
 	/* write out the notes section */
-	if (!write_note_info(&info, cprm))
+	if (!write_note_info(&info, cprm)) {
+		pr_err_ratelimited("Error writing out notes, core dump of %s(PID %d) failed\n",
+			current->comm, current->pid);
 		goto end_coredump;
+	}
 
 	/* For cell spufs */
-	if (elf_coredump_extra_notes_write(cprm))
+	if (elf_coredump_extra_notes_write(cprm)) {
+		pr_err_ratelimited("Error writing out extra notes, core dump of %s(PID %d) failed\n",
+			current->comm, current->pid);
 		goto end_coredump;
+	}
 
 	/* Align to page */
 	dump_skip_to(cprm, dataoff);

@@ -2080,16 +2107,25 @@ static int elf_core_dump(struct coredump_params *cprm)
 	for (i = 0; i < cprm->vma_count; i++) {
 		struct core_vma_metadata *meta = cprm->vma_meta + i;
 
-		if (!dump_user_range(cprm, meta->start, meta->dump_size))
+		if (!dump_user_range(cprm, meta->start, meta->dump_size)) {
+			pr_err_ratelimited("Error writing out the process memory, core dump of %s(PID %d) failed\n",
+				current->comm, current->pid);
 			goto end_coredump;
+		}
 	}
 
-	if (!elf_core_write_extra_data(cprm))
+	if (!elf_core_write_extra_data(cprm)) {
+		pr_err_ratelimited("Error writing out extra data, core dump of %s(PID %d) failed\n",
+			current->comm, current->pid);
 		goto end_coredump;
+	}
 
 	if (e_phnum == PN_XNUM) {
-		if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
+		if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum))) {
+			pr_err_ratelimited("Error emitting extra program headers, core dump of %s(PID %d) failed\n",
+				current->comm, current->pid);
 			goto end_coredump;
+		}
 	}
 
 end_coredump:

243 lines not on this page · raw message

index 0904ba010341..e97c027ce2c9 100644
@@ -42,9 +42,13 @@ extern int dump_emit(struct coredump_params *cprm, const void *addr, int nr);
 extern int dump_align(struct coredump_params *cprm, int align);
 int dump_user_range(struct coredump_params *cprm, unsigned long start,
 		    unsigned long len);
-extern void do_coredump(const kernel_siginfo_t *siginfo);
+extern int do_coredump(const kernel_siginfo_t *siginfo);
 #else
-static inline void do_coredump(const kernel_siginfo_t *siginfo) {}
+static inline int do_coredump(const kernel_siginfo_t *siginfo)
+{
+	/* Coredump support is not available, can't fail. */
+	return 0;
+}
 #endif
 
 #if defined(CONFIG_COREDUMP) && defined(CONFIG_SYSCTL)

index 1f9dd41c04be..3af77048c305 100644
@@ -2880,6 +2880,8 @@ bool get_signal(struct ksignal *ksig)
 		current->flags |= PF_SIGNALED;
 
 		if (sig_kernel_coredump(signr)) {
+			int ret;
+
 			if (print_fatal_signals)
 				print_fatal_signal(signr);
 			proc_coredump_connector(current);

@@ -2891,7 +2893,25 @@ bool get_signal(struct ksignal *ksig)
 			 * first and our do_group_exit call below will use
 			 * that value and ignore the one we pass it.
 			 */
-			do_coredump(&ksig->info);
+			ret = do_coredump(&ksig->info);
+			if (ret)
+				pr_err("coredump has not been created for %s(PID %d), error %d\n",
+					current->comm, current->pid, ret);
+			else if (!IS_ENABLED(CONFIG_COREDUMP)) {
+				/*
+				 * Coredumps are not available, can't fail collecting
+				 * the coredump.
+				 *
+				 * Leave a note though that the coredump is going to be
+				 * not created. This is not an error or a warning as disabling
+				 * support for coredumps isn't commonplace, and the user
+				 * must've built the kernel with the custom config so they know
+				 * that is the case. Let them know all works as prescribed.
+				 */
+				pr_info_ratelimited("No coredump collected for %s(PID %d); "
+					"no coredump support available in the kernel configuration\n",
+					current->comm, current->pid);
+			}
 		}
 
 		/*